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Train antennas

The rail industry requirement and desire to achieve an on-board ‘connected’ environment, for both customer and operational purposes, has resulted in the need for the installation of a wide variety of transmitting and receiving antennas on the rooftop of trains. The physical size constraints of the rooftop mean that the antennas often need to be installed in close proximity to each other, which has the potential to give rise to technical conflicts, particularly interaction and interference issues between the different radio communications systems.

These conflicts have the potential to limit the performance of the radio systems – of particular concern with safety and performance-related communications. Many problems with rail radio systems around the world have been identified to poor train antenna design and deployment.

With the introduction of internet connectivity for passenger Wi-Fi and operational purposes, together with wireless connections for train signalling and satellite positioning, the train antenna is becoming increasingly important and train to ground connectivity will be at the heart of digital rail. 5G radio will probably use both lower and higher frequencies than traditional radio systems. Methods of delivering higher data rates for customer internet use will also be required. All this makes efficient roof-top antennas a very important train body requirement, one that is important for the rail industry to get right.

What is an antenna?

Electromagnetic (or radio) waves are waves of energy that travel through the air at the speed of light. A radio wave can be visualised as a sine wave and the distance it travels to complete one cycle is known as the wavelength of the signal. A 2.4 GHz signal will travel 12.5cm every cycle.

Basically, the magnetic field that the transmitting antenna radiates produces an electric current on any metal surface that it strikes. In a receiving antenna, the applied electromagnetic field is distributed throughout the entire length of the antenna to receive the signal. If the metal that the wave strikes has a certain length relation to the wavelength, the induced current is much stronger. Hence antennas can be ‘tuned’ for the frequency they are required to transmit or receive.

Normally, a radio works on multiple frequencies. For example, the 2.4 GHz band, used by Wi-Fi and Bluetooth devices, has a range of 2,400-2,483MHz. In this band, many channels are used with a frequency-hopping technique, with typically 1MHz between each channel. This means that the antenna has to perform well over a range of frequencies.

Any train rooftop obstruction will ‘block’ the propagation of the signal transmitted or received by the antenna. This results in the signal being reduced and also increases the variability of the signal. Given that a trackside base station may be several kilometres from the train, the signal arrives at the train at a low angle of elevation above the horizontal. Therefore, any obstruction on top of the train impacts on the level of signal. In this situation, the signal relies on diffraction for it to be communicated.

Train antennas need to be certified in accordance with EN50155. This is an international standard covering electronic equipment used on rolling stock for railway applications. The standard includes temperature, humidity, shock, vibration, and other parameters. A train antenna will be typically 40mm to 80mm in height and allow the mutual use of different communication systems, which for example can include; 2m-Band, 70cm-Band/trunked radio/TETRA/UIC, GSM-R, GSM 1800, UMTS, LTE, 2×2 LTE MIMO, 4×4 LTE MIMO, Wi-Fi 2.4, Wi-Fi 5.8 and a Global Navigation Satellite System receiver, all via a single antenna!

Antennas on trains

The ideal position for an external antenna on a train is for it to be as high as possible, although this is likely to be constrained by gauge limitations. Some train classes have almost no space between the envelope of the train and the maximum permitted gauge, although antennas have been specially designed for this situation.

Mounting antennas underneath non-metallic train roofs can be used to resolve the gauge limitation issue. This was incorporated into the antenna systems design for the Class 390, where some antennas are visible on the roof and others are hidden under a non-metallic fairing. The obstructions on the train roofs provide a wide range of challenges to the siting of train antennas; ranging from simple to complex.

A gently curving, uncluttered shape will permit good omni-directional coverage from an antenna placed almost anywhere on or near the centre-line of the roof. Such a simple roof type allows good coverage at low angles in the direction of the front and back of the train for railway-specific communication systems where the base stations are likely to be positioned alongside the track.

The fitting of air-conditioning units can result in significant obstructions being present on the rooftop. Mounting an antenna near to these obstructions should be avoided, as considerable degradation of performance can be expected, particularly if the height of the units is significantly greater than the height of the antennas.

It is not always practical to elevate the antenna such that it is higher than other rooftop items, however the further an obstruction is from the antenna, the higher the obstruction can be before there is a noticeable impact on the signal level.

The tops of air-conditioning units on the Class 390 are about 300mm above roof-level and are typical of train rooftop obstructions in that they block the view from the antenna along the track, both forward and backwards. Any signal that is received via an antenna in the ‘well’ between the air-conditioning units comes predominantly from a signal that is diffracted over the edge of the air-conditioning unit or reflected from objects in the vicinity of the train.

On the Siemens Desiro Class 444, for example, the GSM shark’s fin antenna has been positioned away from the air- conditioning units taking advantage of the large roof area available.

The ground plane is a conductive area on which the antenna is mounted to maintain the correct functioning of most types of antenna. The ‘ideal’ ground plane would be a large, flat, horizontal sheet of metal located above the height of any other object on top of the train, with the antenna mounted centrally on it. In practise, the metal train body is generally used as the ground plane, although some train bodies fall short of this requirement. For example, train roofs are generally curved and, at the antenna mounting point, the roof is often sloped. Fibreglass and composite materials used on some trains do not help the provision of suitable ground planes.

There have reportedly been instances where space has been left on train roof for antennas in the future, but with air conditioning units positioned directly underneath, preventing antenna and cable feeder installation. This is a

good example of the many competing requirements for space on trains, and the need to thoroughly and robustly consider antenna requirements early in the design of a train.

Internal antennas

For Wi-Fi inside train carriages, low profile antennas are available which can be located completely out of sight. Wireless Access Points (WAP) with integrated ‘Smart’ antennas can be deployed. These are more efficient than traditional antennas with higher gain and better interference mitigation which provides better coverage/ capacity. They require fewer and less- expensive cables (data cable vs radio frequency cable), and may be cascaded with a single connection to a switch.

Multiple Input and Multiple Output

A train’s radio channel will be affected by random fading (variation of the attenuation of a signal dependent on factors such as geography) and this will impact the signal to noise ratio, and in turn the data error rate.

In very simple terms the principle of Multiple Input and Multiple Output antennas (MIMO) is to provide the receiver with multiple versions of the same signal. The probability that they will all be affected at the same time is considerably reduced and this helps to stabilise a link and improves performance, reducing error rate. MIMO antenna technology effectively uses multiple antennas at the transmitter and receiver to enable a variety of signal paths to carry the data.

MIMO antenna systems are already widely deployed – an example is Ferrovie del Gargano, one of the largest commuter rail systems in Southern Italy. Its passenger Wi-Fi service uses a hybrid approach using a combination of a Fluidmesh-provided train-to-trackside Wi-Fi system and public LTE. It supports data, VoIP, as well as live video streaming to passengers.

The Ferrovie del Gargano project demonstrates how dedicated trackside wireless networks can be an effective solution to provide on-board connectivity in areas with limited or no mobile radio LTE coverage. The on-board system is provided by two Fluidmesh FM4200 MOBI radios per train connected with high-gain 2×2 MIMO roof antennas. The 5GHz Wi-Fi base stations are deployed along the track with a trackside spacing up to 5km (3.5 miles) delivering 100 per cent coverage. It is claimed that the system provides a Gigabit of usable bandwidth to a train traveling up to 250mph. So, the technology exists, the issue (as often) is how will the infrastructure provide and connect the base stations be funded?

Wireless communications in tunnels has for many years been provided using leaky feeder radiating cables or, for relatively short tunnels and UHF bands, free space antennas. There is now a growing interest on implementing MIMO systems in tunnels with the aim of delivering higher data rates and/or a decrease of the error rate as in free space.

Research by Lille University on propagation mode in tunnels as a means to deliver MIMO has concluded that the challenges can be overcome. In the UK a trial of MIMO over the radiating cable in the Waterloo & City Line is underway to evaluate communication links to customers.

Beamforming

Beamforming is a signal processing technique used in directional signal transmission or reception. This is achieved by combining elements in a phased array in such a way that signals at particular angles experience constructive interference while others experience destructive interference. Beamforming can be used at both the transmitting and receiving ends of a link to improve performance.

Pivitol Commware is one company which is developing a metamaterials beamforming product for what is referred to as Access-in-MotionTM and Holographic Beam FormingTM (HBF). This is aimed at boosting the agility, range, capacity, and spectral efficiency of the communication links for transport sectors (rail, air and sea), while also reducing equipment cost, size, weight and power. HBF objective is to provide high-capacity, long range and interference- avoiding data links, combined with electronic speed beam switching.

5G

Technologies such as massive MIMO, super-dense meshed cells and macro-assisted small cells are being discussed as possible 5G radio access technologies. These may use very-high-frequency bands in the ‘millimetre’ range of the radio spectrum, such as 15GHz through to 70GHz. This spectrum can better support the use of multiple, miniaturised antennas, and more bandwidth is available in these bands than in the bands below 1GHz.

However, millimetre-wave bands do not lend themselves to providing wide area coverage. Therefore, further spectrum below 1GHz is expected to be needed in order to improve mobile broadband coverage. 5G may therefore encompass a range of existing and new bands, which will potentially span a wide section of radio spectrum.

60GHz Wi-Fi for rail?

Traditional Wi-Fi uses either the 2.4 or 5GHz radio spectrum band, but 802.11ad is a relatively new Wi-Fi standard that can deliver speeds of up to 7Gbps using the unlicensed 60GHz radio spectrum band. Known as WiGig, 60GHz is five times faster than current.

Wi-Fi systems with speeds of up to 70Gbps and, by using such high frequencies, the antennas will be a few mm in size. It sounds great, but at these extremely high frequencies the range will only be a few metres and the signal will be absorbed by walls or other physical obstructions. In summary, it’s a very short-range, high capacity, line of sight same-room solution.

However, suppliers are developing micro beam-forming control technology. This rapidly modifies the communication module (in less than 1/3,000 second) should the signal be interfered with in any way, hence getting around the obstruction problem. It could therefore be ideal for use within a train, or from the ground to the train link, although a considerable number of Wi-Fi points would be required.

Fee space optical and terahertz communications to trains

With increasing demand for broadband communications, the radio frequency wireless spectrum is a finite resource that is fast running out. Free space optical (FSO) communications offers another possibility of Gbps data rates for mobile applications without using any licenced spectrum. FSO transmission can be limited by attenuation due to cloud and fog, plus small variations in the refractive index of the atmosphere, however it may be ideal for short- range systems.

The advent of high-power light emitting diodes and highly sensitive photo diodes and simultaneous use as a source of lighting and data communication, has helped the development of FSO as an attractive as well as energy-efficient technique for high-speed data communications.

Channel coding methods are being developed to address the fading issues and provide reliable and high-speed communication channels. Adaptive transmission methods have been used very successfully in fading RF channels for many years, and investigations indicate that significant performance gains may be possible. It is relatively early days for FSO communication, with many challenges to be overcome, but it is another technology for train-to-trackside communications which the rail industry may wish to adopt.

Train radio antenna design is important, but it can involve many compromises and is an area which will become more complex as requirements and technology evolves. It will be essential for both digital rail and customer requirements, and train designers and builders need to involve radio designers at the early stage of a train design. However, with a train body having a typical life of 30 to 40 years and radio frequency technology changing every few years, it is a very challenging subject for all the engineers involved.

Antennas or Antennae?

The word ‘antenna’ is Latin, and means the yard of a sail – the spar that stiffens the sail on a (usually) square-rigged sailing ship.

The Greek word for the same thing was ‘keraia’, but it had another meaning as well – horn. So it came to be applied to the feelers of insects, perhaps because they looked like small horns.

When a Greek text, supposedly by the philosopher Aristotle, was being translated from Greek into Latin, the plural ‘keraiai’ (feelers) was mistakenly translated as ‘antennae’, and the word stuck. So an insect’s feeler became an antenna – plural antennae.

When early radio aerials began to look like long metal feelers, the name ‘antenna’ was adopted, but the engineers involved either didn’t know the Latin source, or ignored it, so the plural became ‘antennas’.

Jargon Buster

FSO: Free-space optical communication – an optical communication technology.

GSM-R: Global System for Mobile Communications-Railway or GSM-Railway.

LAN: Local Area Network.

LTE: Long-Term Evolution telecommunications – similar to GSM 4G.

MIMO: Multiple-input and multiple-output.

TETRA: Terrestrial Trunked Radio (formerly Trans-European Trunked Radio).

UHF: Ultra High Frequency.

UIC: International Union of Railways.

UMTS: Universal Mobile Telecommunications System – a 3rd generation mobile cellular system.

VoIP: Voice over Internet Protocol – also Internet telephony.

WAP: Wireless Access Point.

WiGig: Wireless Gigabit Alliance. Subsumed by the Wi-Fi Alliance in March 2013.

This article was written by Paul Darlington.

 

Bespoke signalling structures for the Ordsall Chord

The Northern Hub programme and electrification scheme will provide an upgraded rail network in the north of England, particularly in the Manchester area, to provide better connectivity, faster journey times and improved capacity. The new track layout, which will allow up to 700 more trains to run each day through central Manchester, will primarily be on masonry viaducts and the new Ordsall Chord railway elevated viaduct, which links together Manchester’s Piccadilly, Oxford Road and Manchester Victoria stations.

Lundy Projects was sub-contracted by Northern Hub Alliance member Skanska/BAM to fabricate and install signal gantry structures, OLE (overhead line equipment) structures and associated foundations. Lundy had also contributed to the design of these structures in conjunction with architectural designer BDP and project lead designer AECOM Mott MacDonald JV.

Having installed its first structure for the project (signal gantry MC466) during the 2014 Christmas blockade, Lundy has commissioned 14 further signal gantries since then.

Gantry mounting

The structures are predominantly sited on Victorian elevated masonry viaducts, which has inherent design and construction constraints. To achieve the end user requirements and to successfully install the structures within a restrictive environment, a variety of substructure and superstructure solutions were required.

Where gauging prohibited the gantry legs to be positioned within the parapet walls of the viaduct, the structures were designed so that the legs would be outboard of the arch piers, mounted on fully welded steel bracket assemblies which were mechanically fixed to the masonry viaduct piers with using a drilled Cintec anchor system and cementitious grout.

The piers were core drilled with an oversized hole and an anchor tendon, formed of a stainless steel threaded bar and an encapsulating fabric sock, which was then inserted into the cored void. Cementitious grout was mixed and injected, under low pressure, through veins to the base of the sock, so filling the void. Once cured, the anchor was then pull-tested to ensure the design strength had been reached.

The stainless-steel bars projected from the wall face, so that the steel mounting bracket could be attached. As the brackets were fixed above quoin level, this design omitted street level foundations, securing the railway from trespass and resultant vandalism.

Project manager Tony Boyle stated: “The works required the fabrication and installation of OLE portals, TTCs (two-track cantilevers) and piles. With only a short lead-in time of two weeks, and installation to be carried out over five 30-hour blockades, both the fabrication and installation teams, including our client Skanska/BAM, had to work in complete unison to deliver the project.”

The steel CHS (circular hollow section) vibro-driven piles were fabricated in Lundy’s robotic facility, which allowed a quick turnaround and mobilisation of site crews within two weeks.

As the REFOS (Rail Edge to Face of Structure) dimensions at some locations resulted in the reach being too great to install the piles from a rail machine, so an off-track piling solution was needed. Skanska/BAM constructed a new haul road and piling mat to allow Lundy to bring in a 35-tonne tracked machine to install the piling and mast in one possession.

The on-track piling was then undertaken with Lundy’s own T10000 Colmars, each fitted with a Movax and BSP hammer attachment to allow the CHS steel piles to be vibro-driven to design total depth. A long-reach Colmar was then used to install the masts.

Once the as-built dimensions had been taken from the piling, this information was immediately relayed back to the fabrication works, allowing the booms to be finalised, galvanised and delivered within a week. Tony Boyle commented: “This close working collaborative relationship forged between Lundy, Skanska/BAM and the client effectively reduced the number of possessions and programme duration from what would otherwise normally be required.”

Architectural harmonisation

Due to the architectural importance of Manchester’s viaducts as they run through the city centre, positioning a visually exposed signal gantry in the heart of this infrastructure required an ‘out of the box’ approach. Signal gantry MC665 is sited on the newly installed Trinity Way steel bridge, part of the new Ordsall Chord track and elevated viaduct, so, although the design had to meet all signal sighting, OLE electrical clearances and gauging requirements, aesthetics was still a major concern.

Signal gantry MC665 is a two-track portal, with three signal dropper cages serving the Up/Down Ordsall Chords in both directions. The route is AC electrified, so the signal dropper cages had to be coordinated around pantograph envelopes while the entire structure needed OLE mesh and solid screens for protection. Fortunately, being sited on a newly designed steel bridge, gauging was not a concern, which allowed the unconventional structure design to work.

MC665 structure was to be harmonised with its surroundings. Working to the architect’s vision, Skanska/BAM and Lundy Projects supplied a bespoke solution.

Unfortunately, from the architect’s perspective, the colour scheme had to remain Network Rail standard black for the boom and signal cages and grey for the legs. However, providing that the structure’s shape and signal position conformed to the standard gauging and sighting requirements, the project was free to change the actual shape. This is where the trapezoidal prism gantry was born!

The gantry’s primary steelwork was fabricated entirely from steel plate, welded together to form the boom cord sections. The legs were again formed from steel plate, shaped as an inclined A-frame, but, significantly, they were designed to be streamlined, without any of the diagonal bracing which is normally used to provide rigidity.

The column shafts were inclined in both cross track and along track directions, forming a trapezoidal prism gantry. The column shafts were also cranked at the base – as they were unseen from the street below, they returned to vertical, which allowed a perpendicular baseplate connection to the bridge deck.

The fabrication was undertaken in one of Lundy’s two fabrication facilities, using the latest software technology and machines to produce the quality needed on such an aesthetically demanding structure. Special jigs and templates were designed to accommodate the different axial directions of the individual plates forming the column and boom section profiles, ensuring they were welded within the tight fabrication tolerances.

To maintain the sight lines of the legs being continued to the boom floor level, each column was spliced below the boom level, with an end-plated connection. This resulted in the ‘join’ being hidden, maintaining the continuity of the leg profile. The leg sections above the splice continued to the top of the boom level and the boom shafts were fully welded between the inside faces of the columns.

The boom sections, which were fabricated from steel plate, were designed with a flange on one edge. The cable trays were fixed to the lip of the flanges which allowed them to be fully accessible but still be hidden from view from below.

To follow the lines of the leg members and the trapezoid shape, the walkway containment handrailing and OLE mesh panels were also set to the same incline as the legs, resulting in a truly bespoke structure that fits in with the design of the new viaduct and also with its historical location in Manchester city centre.

This article was written by Jon Andrews.

An update on Network Rail and RSSB’s COMPASS

No, not a new way of finding where you are going, but a review of the Network Rail and RSSB joint project to find a way of getting the railway operational again, should a significant signalling failure occur.

With Network Rail’s infrastructure being required to provide ever-more capacity in terms of number of trains run, the impact of signalling failures can be very significant. Trains queue up, one behind the other, whilst someone is sent out to site to rectify the problem or arrange for hand signallers to be put in place, maybe also securing the points.

Mitigating this problem formed the main element of the initial COMPASS project, which has now been termed the Degraded Mode Working System (DMWS). COMPASS DMWS is a project aimed at reducing the time to get trains moving again and was first reported in issue 113 (July 2015). Since then, a greater degree of realism has entered the thinking and a meeting with Chris Fulford, the project’s lead engineer, revealed the present progress.

Project objectives

In simple terms, the project will design and develop a system whereby, in the event of a signalling problem, an instruction can be given to a train driver that it is safe to proceed beyond the failure locality to a distant position determined by the signaller. In effect, this is an electronic version of the setting up of present-day Temporary Block Working (TBW), with its associated paper-based instruction giving authority to pass signals at danger. The project will be applicable to both conventionally signalled railways and lines equipped with ERTMS/ETCS. It is not currently part of the Digital Railway initiative, since the technology solution is at an early stage of development.

At this stage, the failure situations are likely to include loss of signalling power supplies, loss of indication at the signalling centre, multiple track circuit/axle counter failures, lineside cable damage and theft. DMWS will initiate checks to ascertain that nothing untoward exists that would prevent a train from proceeding safely.

To achieve this, DMWS must know the accurate position of the train, which track it is on and the intended route it is to take, plus the whereabouts of other trains in the vicinity. DMWS must also know the status of critical infrastructure, such as the lie of the points and whether they are locked in position, or whether the level crossing booms are up or down and road lights are working.

Once these facts are proven, then the signaller can give the driver an instruction (this could be sent within an encrypted SMS text message acting as a data packet) to proceed to the specified distant position. This will be known as an ‘Authority to Move’ (ATM), so as to avoid confusion with a Movement Authority (MA) as used in ERTMS/ETCS train control.

Technical requirements

The means of locally and independently assuring the precise state of a set of points or a level crossing will be achieved by having a COTS (commercial off the shelf) PLC (programmable logic controller) linked to sensors that indicate the points or level crossing status. The PLC will connect to the central system using the GSM-R network radio, fitted with an appropriate SIM card, linked to modems located in the DMWS ground equipment. The radio will be interrogated by the DMWS central system with a separate control screen being provided at the signaller’s work station, which will normally be switched off and only activated when required.

Initially, the PLC will be programmed only to inform on the current position of the ground equipment, but more adventurous commands are foreseen once the system is proven. The PLC will constantly receive points and level crossing status information, not just when a failure condition occurs. It is possible that the GSM-R system might also have failed, for instance if a cable has been cut that feeds the nearest base station, and, to guard against this, the radio unit will comprise a public mobile receiver as a secondary unit, with the combined unit being a dual-band receiver.

So much for the trackside and control centre units, but what will be needed for the train-borne kit?

A means of communicating the ATM instruction to the driver has to be available. This can either be a free-standing unit in the cab or, more likely, the COMPASS DMWS facility could be built into existing systems such as the train borne DAS (Driver Advisory System) unit or perhaps the next generation GSM-R voice radio. The latter will have considerable computing power and a Rail Engineer article in issue 129 (March 2014) described the additional uses that might exist in the new generation of train mobiles, including facilitating DAS information on its screen.

DMWS will need train position to be reported to the signaller on a near-constant basis and this implies the use of GNSS (Global Navigation Satellite System). The new generation of train radio will have a GPS input, and thus the feed for this will be readily available. It is, however, the intention that the train and freight operators will be free to choose whatever equipment suits their own fleets.

Whilst DMWS is seen as a natural addition to the operational management systems within the new Railway Operating Centres (ROC), there is no reason why it cannot be deployed in any IECC (Integrated Electronic Control Centre) or power signalbox. Indeed, if the expected advantages are to be realised, the pressure will be to deploy it as widely as possible.

Progress to date

The 2015 intention to pursue a trial on the ECML did not materialise, beyond fitting some test infrastructure monitoring equipment to the three nominated locations between Doncaster and Peterborough.

A more pragmatic way forward is now progressing, with a three-part R&D programme. Part 1 consisted of an invitation to 13 companies, issued in early 2015, to bid for producing a feasibility study on how a DMWS system could be progressed.

Five of the 13 companies were awarded a contract in September 2015 and invited to submit a further bid for Part 2, entailing production of a laboratory-based simulator to demonstrate how a DMWS would operate in practice, including the integration of the various sub-systems.

From the feasibility studies and proposals received in Part 1, and after the relative merits of the responses had been assessed, two companies – Thales and Altran proceeded to build a simulator, Altran in Bath, Thales in Cheadle Hulme, the work taking place between March and December 2016.

Additional studies were included in the work packages, such as RAM (Reliability, Availability, Maintainability), safety and security, and human factors implications. Both companies were also required to submit a proposal for Part 3 – the building of a functional DMWS demonstrator.

The two simulations, together with their associated deliverables and the proposals for Part 3 were duly assessed, with Altran being awarded a contract extension for Part 3 in February 2017. This will involve provision of a real demonstration on the Hertford Loop test track. The line is double track, but the infrequent train service allows one of the lines to be used outside of peak hours for testing purposes and it is where the ETCS integration / interoperability tests have taken place. The single line has no points or level crossings but these will be artificially inserted into the test section using the real points and level crossings that exist in the Network Rail Walsall training centre – it’s amazing what can be done with Network Rail’s in house broadband transmission links!

The test train used for the ETCS work (a Class 313 EMU) will be fitted with the train-borne DMWS equipment, including the necessary GPS satellite tracking picture and ‘distance to go’ count down. The signaller’s control panel will be fitted in one of the test control rooms for the line, located at the Hitchin ERTMS National Integration Facility (ENIF).

GPS co-ordinates for the relevant track geography (such as signal locations) will be provided by translating video images that already exist of the railway using the Systems Data Exchange Format (SDEF), thus enabling the infrastructure information to be linked to the GPS location.

A two-week trial slot is allocated for January 2018. During the test period, the train driver will not be expected to directly take part in the trial as this may cause confusion with other test programmes. The DMWS ATM instructions will be monitored by Altran test engineers, who will instruct the driver accordingly.

Altran will have the responsibility for proving that the combination of GPS positioning, points-lie information and historic berth occupancy is capable of determining which track the train is on. It is hoped that the on board requirements can be largely incorporated into the new Siemens GSM-R voice radio which will have 4G and WiFi capability as well as GPS positioning and a modem, thus being able to switch from GSM-R to other radio modes.

Safety implications

Since the Hertford Loop site already has a safety case as a test track, the demonstration work can be carried out without any new safety requirements needing to be specified. No trackside infrastructure needs to be fitted, as this will exist in the safe environment of Walsall training school.

DMWS will need to effectively disconnect the point machine or barrier mechanism from the interlocking, as to initiate commands from two sources during the period of disruption could be confusing and compromise safety. DMWS may also suppress any TPWS operation within the failed area so that trains will not have to stop for the driver to manually isolate the on-board TPWS equipment.

Following this, an operational trial should take place on a chosen piece of railway, which will then need a separate safety case to be produced. However, since DMWS is essentially an electronic version of the long-established manual means of setting up temporary block working, it is anticipated that the safety procedures used for the latter can be the basis of the DMWS intentions.

Ongoing vision

There can be little doubt that, if successful, COMPASS DMWS will become an important tool to get trains moving again more quickly when degraded operation is necessary. With the ability to assign the length of the DMWS block section, and with the train’s movement regularly updated, it will give the signaller much greater control than the manual ‘man on site’ situation existing currently.

It must be emphasised that the system is only an aid to operation, recognising that the signaller and driver remain in control. DMWS is essentially a way of enhancing the communication protocol in getting an instruction to move a train from point A to point B.

Once the system is proven in operation, the ongoing vision extends to using DMWS to initiate an instruction that would move a set of points for the intended route and for level crossing activation to commence. Indeed, the level crossing sequence at Walsall has already been activated by a similar type of remote command, as have points at Doncaster training school. However, that is for the future, and it is very much one step at a time for now.

The immediate ongoing work will be to complete the practical demonstration, produce a business case and the writing of a procurement specification for an operational trial. All these will need to embrace the use of COTS equipment as the justification for proceeding will need to minimise the amount of financial outlay required.

The total number of DMWS trackside units to be procured could be considerable as one unit is only expected to monitor one or two sets of points or one level-crossing site. An analysis carried out at Didcot showed that up to 36 units would be needed to cover all the various junctions.

DMWS deployment will need to link into the railway’s business performance model and will be prioritised to the most vulnerable inter-city and major city suburban routes.

Rail Engineer will continue to monitor the development of this fascinating project and will report progress from time to time.

This article was written by Clive Kessell.

Network Rail begins Southend Victoria branch OLE renewal

Photo: Network Rail.

Network Rail has begun a £46 million project to renew the overhead lines on the Southend Victoria branch line.

More than a kilometre of new OLE wire has been installed between Shenfield and Billericay. In total, Network Rail will have replaced 128km of overhead line by the end of the year.

The renewal will improve reliability on the line, reducing the number of failures caused by the ageing OLE infrastructure.

https://youtu.be/cK2LPKkR3Fo

The overhead lines on the Southend Victoria branch line are some of the oldest in the country and speed restrictions are a common occurrence in hot weather.

Meliha Duymaz, Network Rail’s route managing director for Anglia, said: “We recognise the issues our Southend passengers face in summer when services are delayed because of sagging overhead wires.

“We’re installing a new overhead wiring system to improve the reliability of train services as part of our Railway Upgrade Plan and we’ve fast-tracked the work so passengers can start seeing the benefits as soon as possible.”

Green Trough polymer cable-troughing system

Green Trough through a tunnel.
Green Trough through a tunnel.

The traditional method of cable routing is by using ground-level concrete troughs which are heavy to carry and difficult to install without the aid of lifting equipment. Prone to cracking and spalling, which over time will lead to their failure, concrete troughs can’t be easily modified at a later date to accommodate cable entry or exit points.

Other materials have been tried, including wood, asbestos and plastic. All of these were expensive to install. Wood quickly rotted while asbestos was fragile and still presents an expensive maintenance problem for asset managers with its associated safety hazards. Some plastic and polymer-based products suffer from expansion and contraction problems, buckling lids, collapsing lids from ballast compression on the sidewalls. They also burn when ignited or float in water. All of them fail to provide adequate cable protection.

Recognising back in 2002 that cable containment and protection is an essential part of communication, control and power networks across a diverse range of civil infrastructure projects including rail, highways, power and water, the Furukawa Electric Company (Thomson Reuters Top 100 Global Innovators 2013, 2014) began testing a new type of trough manufactured from a 100 per cent recycled polymer.

Their objective was to design and manufacture the world’s first complete polymer cable troughing system. Capable of being deployed rapidly and installed safely by one person without the need for lifting equipment, Green Trough was born.

Made from a 100 per cent recycled polymer, Green Trough is a versatile, environmentally friendly and durable product, designed to carry power and communications cabling anywhere – horizontally, vertically, at an angle, around an obstruction, along a wall, as a walkway, or even in an elevated position. Units have built-in anti-vandal and anti-theft features with lockable lids to help deter cable theft.

As a proven system, it is installed throughout Japan’s railway networks — including the Tokaido Shinkansen, which carries the record-breaking Bullet train. Launched in 2005, following a period of intensive R&D, the complete polymer cable-troughing system is now installed on major global infrastructure projects and was winner of the Best New Electrification Product at the Infrarail and CITE Awards in 2014.

Offering a diverse range of components, the system includes straights, curves, junctions and gradients, all available in a range of sizes comparable with concrete, but with greater internal capacities.

Key Benefits

Connecting the units is simple and any combination of troughs is possible. With a male and female connector moulded at the end of each duct, no joint grouting is required. Pan and tilting flexibility in the joints also means a bending angle of 2° to 5° can be achieved, enabling the route to form a natural minimum radius of 13 to 15 metres. This flexibility makes laying the units on uneven surfaces much easier and they can effectively be installed into various ground types, including ballast, soil (or a combination) and as a free-standing cable-troughing route. Green Trough can also interface with other troughing systems.

Made from a 100 per cent recycled polymer, the system complies with HSE manual handling requirements and was awarded a green rating on Network Rail’s Manual Handling Assessment Chart (MAC). Weight savings of up to 83 per cent mean that Green Trough significantly reduces transport and on-site handling costs.

Troughing units are easy-to-cut with hand tools, without creating smoke or dust. A range of accessories is available, to allow cabling to branch off or interface with existing concrete routes.

The polymer’s thermal coefficient of expansion has been determined and used to design a sacrificial ‘pip’ that is moulded into the connection at the female end of the unit. In extreme temperatures, these ‘pips’ absorb any expansion that might occur without distorting the trough route, so preventing buckling.

If enhanced capacity is required for future proofing with extra cables as part of any upgrade at a later date, Green Trough offers much more internal capacity and design options than many other troughing products.

The whole life costs of installing Green Trough are very favourable, with an expected lifespan of over 50 years.

Delivering value

Green Trough is rapidly becoming the product of choice where versatility and speed of installation is paramount. It offers installers a truly customisable solution and is available from TTS Rail, a leading supplier of polymer cable troughing to Network Rail and UK rail infrastructure companies.

TTS has built-up an unrivalled wealth of expertise in the rail industry over the years and provides off-the-shelf and bespoke polymer troughing solutions. Its configuration team works with organisations, designing tailored solutions for specific project challenges and assisting in product configuration to find the most cost-effective outcome. A unique range of accessories offer more scope for customisation on-site.

A recent configuration project for Balfour Beatty was to install large TTS 430 series troughs on the London Bridge station approach viaduct, part of the Thameslink Programme – Key Output 2. This complex project involved a suspended trough route on both the top and the outside of the viaduct walls, navigating many fixed obstructions and safety recesses along the route. Balfour Beatty designers worked closely with the TTS configuration team to develop the optimum route, keeping the bespoke units to a minimum.

Following the most recent audit, TTS has been awarded the latest ISO9001:2015 Quality Management System standard certified by BSI, demonstrating a continuing commitment to the highest levels of quality management and customer satisfaction.

Green Trough Walkway

Working in conjunction with Network Rail, TTS has designed the Green Trough Walkway system (pictured below). Having recently gained product acceptance, its hard wearing, non-slip and safe surface is ideal for troughing routes where a low-to-zero maintenance walkway is required, often found near depots, stations and signalboxes.

The product was recently installed at a key work section of the Crossrail Anglia project, prompting a Costain section engineer to comment: “The TTS Green Trough Walkway was selected as the ideal product to resolve issues which can be found at many infrastructure sites due to the heavily congested nature of ageing assets. One of the greatest benefits of Green Trough is the flexibility it provides from construction to operation. Light to transport and install, versatile to fit around existing infrastructure; the safe and solid walking route provides a robust and resilient solution.”

Consisting of two TTS 300 series units (the equivalent of two C/1/29 concrete troughs) joined together in parallel pairs with steel straps to ensure stability, individual access and integrity of the lids, this durable, combined walkway and troughing route is easily assembled by a two-man team and offers significant on-site benefits compared to other systems:

  • Non-slip, 780mm-wide walkway surface;
  • Zero-static build-up for pedestrians;
  • UV resistant;
  • 105,000mm2 internal capacity;
  • Easy access without lids buckling or becoming dislodged and unstable.

Elevated System

Network Rail had a requirement for an elevated system specifically designed to provide above-ground level cable management. TTS designed a simple, but effective, supporting mechanism that can carry multiple independent cable-containment trough routes.

Galvanised steel posts, concreted into the ground at two metre intervals, support ladders and horizontal bends bolted to brackets suspended from the posts. One-metre Green Trough units sit in the ladders connected to each other, forming a continuous run. Developed for use with three of the Green Trough series; TTS 90, TTS 150 and TTS 200, the system is simple to install and can carry one, or up to four, cable-troughing routes.

Fast, Flexible and Efficient

Green Trough has proven its capabilities for quicker installation, faster maintenance and improved worker safety over the years in the Rail industry. It is now used across a growing range of market sectors where cable containment and protection is an essential part of the infrastructure. Recent site applications of Green Trough have included a water treatment works for United Utilities, Sellafield nuclear fuel reprocessing, solar farms, Celtic Park football stadium and highways power and comms to name but a few.

Keeping things simple while helping customers solve their troughing problems, Green Trough is delivered in kit form on a pallet, with all the units needed to complete the job.

Big data – a new approach to risk analysis and safety management

Big Data Risk Analysis (BDRA) is a new approach to risk analysis and safety management for the railway industry. Led by the Institute of Railway Research and RSSB, it is based on the intensified use of vast amounts of safety-relevant data, analytic software, non-relational databases and powerful computer systems.

A recent conference on the BDRA programme, held in Birmingham was attended by representatives from Japan, France, Sweden, USA and Korea, had academic representation from the universities of Huddersfield, Birmingham, Cranfield, Lumera (USA) and Imperial College London, and attracted delegates from the air transport industry.

The safety performance of Britain’s railway has improved dramatically over the last 50 years. In the 1960s, up to 100 workers a year lost their lives, while now, in some years, no fatal incidents occur at all. This much-reduced number of incidents makes further improvements more challenging, and so new methods of identifying risks and control measures are needed, which is where BRDA comes in.

Proactive to reactive

In very simple terms, any safety management system consists of three elements – plan, act and review. This can be further broken down into the need to define the objectives, risks, and control measures, then to monitor the improvements and feed them back into a modified plan. Investigations following incidents identify new control measures but, because there are now fewer incidents, new ways of identifying control measures are required. Put another way, safety improvements need to become proactive rather than reactive.

The basic tools of BDRA have been developed by the University of Huddersfield and RSSB, with the objective of an integrated approach to safety and risk assessment, based on data-analytics. It is still early days in the programme but, looking to the future, state-of-the-art risk monitoring technology could pinpoint faster, targeted improvements to safety and reliability on Britain’s railways at the push of a button. The vision is that it will provide the right insight, to the right person, to help them make the right decision.

This technology is already applied in the oil and nuclear sectors and could supply tomorrow’s rail safety manager with a real-time ‘intelligence console’ about incidents, infrastructure and rolling stock faults, providing rapid tactical analysis and automating parts of the existing paper trail. It will also give better information for efficient and robust boardroom decisions.

Challenges

There are many challenges to overcome, such as sharing information between companies, privacy and security, capturing data in a consistent format, and making sure the analytic process allows appropriate human cognitive review. What it must avoid is data overload to engineers and managers so that they can’t see the wood for the trees. What BDRA must do is to extract intelligence from multiple data sets – ideally, in real time.

The Rail Industry’s Data and Risk Strategy, published by RSSB and steered by a cross-industry group, sets out how the railways can make better use of data to improve safety performance, prevent delays and disruption, retain high productivity and reliability, and prevent train accidents.

The first step of the strategy is already in place, with the new Safety Management Intelligence System up and running, and actively in use by Network Rail and train operating companies. SMIS+ is the programme to modernise safety-reporting capabilities, making it easier for people to collect information, and extract intelligence. This could reduce the time taken, from first being alerted to incidents and close calls to making the ultimate remedial decision or investment to manage the risk, from years to weeks in some cases. It will make it easier for companies to report and track safety incidents and investigations, and provide the right risk information in the right format to the right people at the right time.

SMIS+ is a completely new, cloud-based on-line system exploiting commercial off-the-shelf, state-of-the-art safety management software which has replaced the old SMIS. So, while the name is similar, this is a completely new system, denoting a transformation in system capability.

Phase 1 was introduced on 6 March 2017, replacing the old SMIS system, with phase 2 being rolled out later in the year and replacing the existing close call system. This will deliver the ability to record and track ‘close calls’, as well as the ability to use mobile devices.

SPAD management.

Improvements by the industry mean that the risk from signals passed at danger (SPADs) is low, and it is over 17 years since the last fatal train accident was caused by a SPAD. To make the next step in risk reduction, though, it is necessary to look deeper into the circumstances that cause a SPAD, such as how frequently a signal is approached while showing a red aspect.

Rail companies will be able to identify the signals which are most frequently approached at red thanks to a new on-line tool developed by RSSB and the University of Huddersfield. The tool can help to focus attention on signals where SPADs may be more likely. It has been proven successful in trials and it is hoped that it will be used to generate new safety and performance insights for rail companies.

The Red Aspect Approaches to Signals (RAATS) tool uses 420 days of train movements provided by Network Rail through its open data initiative and applies complex algorithms to identify where red signal approaches are happening. The results can be broken down by train type, day of the week or time of day and analysis can be carried out on signal groups. Users can interrogate data within the tool or export it into Excel.

The RAATS tool was released as a prototype in January, and work is underway to refine it, including linking it to live data feeds, before formally launching it later in the year. Looking to the future, it should be possible, with the right collaborative industry approach, to integrate data from on-train monitoring recorders with signal asset condition and maintenance databases, using a BDRA approach to provide a complete proactive SPAD risk management system.
SNCF SPAD experience.

In France, SNCF has also been working on a similar analytical risk system for its SPAD management. It has managed to integrate a year’s worth of on-board data, but identified that the data was overwritten in all the recording systems. This is one learning point for any BDRA system.

The experience of having scattered data across the French network was not an issue, but data quality was a bigger problem, with the accuracy of geographical and time data being vital for robust analytics. Good results have been achieved using text analysis, and those from machine learning supervised classification algorithms are encouraging.

SNCF admitted that the project’s access to the company’s data could have been better and that its IT systems can’t access all the required data across the network. There are also plans to merge event reporting from other sources, such as signal asset data, performance and maintenance records.

Text analysis

Peter Hughes of Huddersfield University explained a process of text-analysis of cold calls, which is one of the tools of the BDRA system. To analyse and identify risk from free-text cold calls requires a very carefully designed set of algorithms to make sure nothing is missed and to provide intelligence to enable improvement plans to be implemented.

NoSQL is the next-generation database used at the heart of the text-analysis system. These were originally called ‘non-SQL’ or ‘non-relational’ databases, reflecting the fact that the database provides a mechanism for data storage and retrieval which is modelled in other means, rather than the tabular relations used in relational databases. NoSQL databases are used by the likes of Facebook, Google and Amazon, and are increasingly being used in big data and real-time applications.

The text analysis is designed to pick out and highlight key terms in free text messages. The requirement is to identify common hazardous events, regardless of the language. It must take into account that the free text may have been generated by a user who may be wearing gloves, stood in poor light and lineside in freezing rain! So, for example, “access” could be entered as “acces” “possession” entered as “posession”. The NoSQL database takes this into account.

This article was written by Paul Darlington

 

Elizabeth line track installation complete

The final clips have been installed on London’s Elizabeth line, completing the track work for the capital’s £14.8 billion railway.

The final piece of track was firmly secured in the eastbound tunnel of the new Whitechapel station earlier today (September 14). In total, more than 50km of track has been laid for the project.

Secretary of State for Transport Chris Grayling, Deputy Mayor for Transport Val Shawcross, Crossrail chairman Sir Terry Morgan and chief executive Andrew Wolstenholme were on hand to mark the occasion at an event this morning.

Sir Terry Morgan said: “The completion of the permanent track brings us another crucial step closer to the Elizabeth line opening in December 2018.

“We’re delighted to be officially marking this important milestone as it also signifies a great achievement for all the dedicated men and women who are working on the project. The Elizabeth line will transform rail travel across London and the South East for millions of passengers with faster journeys, less congestion and improved travel links for a better connected London.”

Photo: Crossrail

International rail insights from Sochi

The Strategic Partnership 1520 is an annual international forum which considers common technical and commercial issues for rail businesses operating on the Russian-gauge network. This year, the twelfth forum was held in the Caucasus mountains at Rosa Khutor which, together with its railway line, had been built for the 2014 Sochi winter Olympics and is now a thriving mountain resort.

Although the forum is primarily concerned with 1520mm-gauge railways, it offered an international perspective well beyond this with speakers from Cuba, France, Germany, India, Iran, Poland and Sweden.

International projects and exports

RZD International, an engineering company within Russian Railways, has recently undertaken significant projects in Iran, Serbia and North Korea. In 2015, it won a contract worth €1.2 billion to electrify the 495km Garmsar to Inche Bourun line in Iran, which will increase its annual freight traffic from 2.5 to 10 million tonnes. In Serbia, it has reconstructed 372km of railway with numerous bridges and tunnels that raised line speeds from, typically, 30km/h to 120km/h.

The company now has prospective projects for large-scale infrastructure repairs in Cuba, the operation of a 1,537km line in Brazil, line speed enhancements in India and new lines in Indonesia (200km) and Vietnam (242km).

With government support, Russian train builders are increasing their exports, although they cannot compete in Northern Europe and North America due to sanctions.

Transmashholding has a plant in Kazakhstan to build locomotives for use there and export to Turkmenistan, Kyrgyzstan, Tajikistan and Azerbaijan. In 2015, the company won a €45 million competitive tender against Alstom and CAF for refurbishment of 222 Budapest subway cars and, in an €88 million contract, has supplied 27 DMUs to Serbia.

Sinara Transport Machines, a manufacturer based in Ekaterinburg which partners with Siemens in Ural Locomotives, currently has contracts worth €196 million to supply Cuba with 74 four-axle hydraulic locomotives and 80 two-axle rail buses.

Cuba, India and Iran

Presentations at the forum gave an interesting insight on the development of these very different railways. Eduardo Davila, Cuba’s Deputy Minister of Transport, described the problems faced by the country’s aging 4,226km railway network and rolling stock. He advised that, with Russian cooperation, Cuba plans to increase rail traffic between 2016 and 2022, with freight rising from 15 to 22 million tonnes and passengers from 13 to 42 million.

In contrast India’s 66,687km rail network is the world’s fourth largest. Minister of State for Railways Rajen Gohain described plans to extend this by 7,900km by 2030 and to electrify 24,400km by 2021. This includes the construction of two dedicated freight corridors totalling 3,360km and a combination of high-speed lines and speed improvements on what Gohain described as the golden quadrilateral and its diagonals. These are the rail links between Delhi, Mumbai, Kolkata and Chennai.

Over the next five years, India plans an investment of €114 billion on its railways, of which 15 billion will be spent on the redevelopment of 400 stations.

The president of the railways of the Islamic Republic of Iran, Saeed Mohammadzadeh, described the development of various international freight corridors through Iran and, in particular, the North-South Corridor which is the sea route from Mumbai to Bandar Abbas and the standard 1520mm gauge railways through Iran, Azerbaijan and Russia to Moscow and Helsinki. 1,915km of this route is through Iran.

This corridor was only recently completed with the opening in March of a railway bridge over the river that forms the border between Iran and Azerbaijan. As a result, containers can now get from Mumbai to Moscow in 22 days – twice as fast as the sea route through the Suez Canal.

Digital Russian Railway

Many presentations featured the challenges and opportunities presented by digital technology. Although these were often similar to those in the UK, there were new ideas and applications specific to Russia. Presentations from Siemens referred to UK practice with mention of unmanned Thameslink trains (something lost in translation) and an illustration of train departure indicators at Euston showing the available space on trains.

Senior Russian Railways vice-president Sergey Kobzev explained the objectives of the company’s digital railway project and how this compared to European and US practice. In Russia, it has three parts: customer applications, traffic requirements (control and infrastructure maintenance) and IT services.

Various speakers stressed the importance of cyber security and the need for open data, especially for customer applications. In his presentation, Michael Peter, CEO of Siemens Mobility Management Business Unit, offered a solution to these apparently conflicting requirements in the form of a “data diode”.

Oleg Valinsky, Russian Railway’s head of traction directorate, described various rolling stock digital innovations, including embedded diagnostic systems, the remote control of shunting locomotives, the use of augmented reality as a maintenance aid, infrastructure monitoring by service trains and driver information ranging from gradient profiles to dynamically reconstructed timetables. Providing drivers with such real-time updates of their train schedule, together with other initiatives, are saving around 450 million kWh each year.

With each modern train generating, typically, a terabyte of data each year, effective data mining is essential. One such solution is the Siemens Railigent platform, which offers a smart monitoring, data analysis and forecasting service for asset management. In February, a data processing and analysis centre using Railigent was opened at Podmoskovnaya depot in Moscow, with the intention of improving train and infrastructure reliability and gradually moving to condition-based maintenance.

The new Silk Road

China and Russia have signed agreements on a “belt and road initiative” for economic development along enhanced transport corridors, from East to West, through Russia and Central Asian countries. A key part of this initiative is the development of railway corridors to attract containers currently carried on ships.

First vice-president of Russian Railways, Alexander Misharin, advised that the company’s priorities for this are electronic consignment notes, unified train lengths, improved logistics and infrastructure improvements at border crossings. China shares these priorities, as increasing container transit traffic was part of its development plan.

In 2016, rail transit routes carry containers equivalent to 155,000 twenty-foot equivalent units (TEU) from China to Europe, with half this traffic carried in the reverse direction. This is twice the number of containers carried in 2014. 68 per cent of this traffic is via Kazakhstan with the remaining 32 per cent travelling over the Trans-Siberian Railway.

Currently, container trains travel 700km per day. The intention is to raise this to 1,000km by 2020 and 1,700km by 2030.

Misharin commented that, with increasing trade and China’s promotion of overland container traffic, it was possible that a million TEU could be carried by 2020. A significant factor is the growth of e-commerce from the Asia-Pacific region, which is currently worth a total of €930 million with the main players being China (€674 million), Japan (€101 million), South Korea (€57 million) and India (€22 million). The respective rate of growth for these countries is 33, 7, 11 and 130 per cent. India’s rapid rate of growth is an indication of the need for its ambitious railway expansion programme

To respond to this growing e-trade, fast transits are required. The proposed 7,761km high-speed rail line between Moscow and Beijing, which is expected to be operational by 2030, will deliver these, giving a 33-hour journey time between the two cities. Misharin also suggested that Russian Railways will require 300km/h cargo trains carrying 600 tons of goods. These will have wide doorways through which aircraft style containers can be loaded.

Currently, rail carries less than one per cent of the container traffic between Asia and Europe. Misharin considers that there is the potential for Russian land corridors to carry 25 per cent of high-value goods traffic.

High speed to Kazan

In 2013, Vladimir Putin announced the plan to build a 762km high-speed line between Moscow and Kazan, which will be part of the high-speed line to Beijing. The €268 million design contract for this line was let to a Chinese consortium in 2015. Currently, design of the 230km section between Moscow and Nizhny Novgorod is finished, with the remaining designs 42 per cent complete.

The line will have a bespoke ballastless track system and will require 211 overbridges and 113 underbridges – a total of 150km will be over man-made structures. The line’s estimated cost is 16 billion euros and 373,000 workers will be needed to build the line which will require 4.4 million cubic metres of reinforced concrete and 354,000 tonnes of steel. 85 per cent of raw materials, supplies and equipment for the line will come from Russia.

The line is designed for 360km/h operation and will reduce the Moscow to Kazan journey from its current 14 hours 7 minutes to 3 hours 30 minutes. Misharin advised that, with 20 per cent of Russia’s population living in territory adjacent to the new line, it had been estimated its cumulative benefit to the Russia economy by 2030 will be €280 million and increase regional product growth by 60 to 75 per cent.

He announced that, by 2030, Russia plans to have extended the Kazan high-speed line to Ekaterinburg and to have constructed further high-speed lines to St Petersburg and Sochi. However, he did not announce any date for the start of construction for the high-speed line to Kazan. Whilst the line is in an advanced stage of development, it would seem that arrangements for its funding have still to be finalised.

Making the pie bigger

In his closing speech, Oleg Belozerov, president of Russian Railways, noted how the forum had focused on digital technologies, human resources and logistics. He felt that cooperation was the only way to deliver global projects as the intention should be “to make the pie bigger” rather than seek individual advantage. He encouraged the development of complex railway projects abroad that could make a significant contribution to each country’s national economy.

He felt that, with 20 agreements being signed and an attendance of over 1,090 participants and 107 speakers from 337 companies in 24 countries, the forum had been a great success.

There were also 145 journalists present. This one was particularly impressed by the way Russian Railways has adopted new technologies and its development of transport corridors. With its vast size, few economies can be so dependent on their railways as is Russia. For the future, Russia is set to be at the centre of a new Silk Road, which will be an engine of growth for the Eurasian economy.

This article was written by David Shirres.

 

Shoreham Viaduct undergoes major refurbishment

An essential and significant infrastructure asset in the very well-used southern railway coastal route between Brighton and all points westward is the 16-span Shoreham viaduct, which carries the railway across the tidal estuary of the River Adur.

The present viaduct, which was completed in 1892, has a superstructure of early steel simply supported on concrete-filled cast-iron caissons. With its marine situation, it has needed much maintenance attention over the years, the most recent being in 2004. In addition, during World War II, Shoreham viaduct was damaged by bombs on at least three occasions.

Now, however, Network Rail has commissioned a very comprehensive refurbishment to give it a new extended lease of life. BAM Nuttall is the principal contractor, managing the project which is to repair and replace areas of the steelwork suffering loss of section through corrosion, along with comprehensive grit blasting and repainting of the entire structure.

Preliminary work

The main works commenced in April 2016 and will be completed by December 2017. However, prior to the actual refurbishment work, an ancillary major task was carried out, between August and October 2015, to remove a redundant gas main attached to the south face of the superstructure. This enabled approximately 100 tonnes of dead load to be eliminated from the structure – prior to the addition of alternative, but essential, dead load in the form of the extensive steel plating repairs to cross and main girders throughout!

The removal of the gas main was accomplished by working in midstream from a barge provided by Jenkins Marine and over the soft, silty shore areas by using a load-spreading paving of 100mm thick Durabase mattresses.

Assessing its condition

Mott MacDonald, the consulting civil engineer for the work, prepared outline design proposals based on the available preliminary data concerning corrosion and section loss.

Two previous heavy maintenance packages have been carried out on the viaduct in recent years, firstly over one half of the structure during the 1990s and secondly on the remainder of the structure in 2003/4. Records of girder conditions from these works were used to estimate the scale and scope of works necessary for the current project.

However, once the structure was fully scaffolded and access became available, Mott MacDonald was able to conduct a comprehensive and up-to-date corrosion survey and use the results to refine the exact specification required for every individual cross girder, main girder and component throughout the viaduct.

There was a considerable variation in what was required where. Therefore, to simplify the specification of the work as far as possible, a suite of repair categories was devised and drawn up in detail. For example, in the design schedule for repairs to the cross girders, there were eight different specifications, dependent upon the location and extent of corrosion loss. So, although all 69 cross girders throughout the structure are essentially identical, each end of each individual cross girder has been designated with its own specific repair type, from 1 to 8, depending on what is required.

This approach has targeted the work required to the structure, which has required collaboration between all parties to assist with the planning of the work, the ordering of materials and the pre-fabrication of the steelwork repair plates.

Access and protection

Underslung scaffolding across the entire structure was designed and installed by Hadley Scaffolding and provides easy access to every part of the superstructure being repaired and painted. Optima Scaffold Designs checked the safe loading and structural performance of the scaffolding. Mott MacDonald assessed and checked the viaduct’s structural capacity to take the additional loading from the scaffolding.

The entire scaffolding is covered by shrinkwrap cladding to minimise the effects of wind and wet weather and to contain the grit and scalings from blasting, essential as the Adur estuary is a Site of Special Scientific Interest (SSSI). Approval for the method of work to safeguard the SSSI was sought from several authorities, including the Environment Agency, Natural England, West Sussex County Council and the Marine Management Organisation.

One innovation at Shoreham viaduct is the use of a biometric security system. Everyone who works on the site has their details, which includes a copy of their index fingerprint and a scan of their CSCS (Construction Skills Certificate Scheme) card, logged into the system. Entry to the site is via a turnstile, which only responds to a biometrically recognised fingerprint.

Another sophisticated feature that BAM Nuttall has introduced is a wireless emergency fire and first aid point. If the fire alarm is triggered, the turnstiles revert to free wheel, allowing safe and quick egress. The system prints out a list of all who have entered the site, thereby enabling a roll call.

Possessions not required

It is striking that almost all the repairs are being carried out without the need for track possessions, although these formed part of the original design. However, an innovative approach to the repair of those cross girders suffering bottom flange corrosion resulted in a reduced requirement.

Because of the extensive nature of corrosion to some of the cross girder bottom flanges, and the consequent difficulty of achieving a good seating surface for the addition of conventional strengthening plates, an alternative solution has been devised by Mott MacDonald.

eavy angles are being attached to the cross girder web, slightly above the bottom flange, running horizontally in those locations where there is a need for strengthening.

In order to fit these angles, it is necessary to curtail some of the stiffeners running between the top and bottom flanges. This alteration to the stiffeners cannot be done whilst the structure is carrying live load. After the new horizontal angles are installed, along with replacement stiffeners and web repair plates where required, the cross girder can once again go back into service.

This article was written by Mark Phillips

 

Formal methods for signalling interlockings

A stock photo of a signalling workstation. Credit: Network Rail.
A stock photo of a signalling workstation. Credit: Network Rail.

Back in the day of mechanical signalling, it was comparatively simple to prove that signalling interlockings did what they were supposed to do. There were drawings to study and a finished mechanical system that could be tested. The interlockings themselves were fairly limited in their application, perhaps covering one junction or, at most, a series of junctions such as at a station throat, but it was all fairly comprehensible.

Then along came computer systems. Suddenly, the problem was immeasurably more complex. Every line of code could alter how the system worked and interlockings grew to control larger areas, introducing possibilities of more interactions. So how to check it? With teams of computer experts who were also signalling engineers, or signalling engineers who were also computer programmers, laboriously going through the program line by line?

A sensible and standardised approach was needed. So-called ‘Formal Methods’ are mathematical techniques used to specify, develop and verify computer programs and systems. They seemed like obvious candidates, but would have to be modified to work on safety-critical signalling systems.

Railway Industry Association Standard 23, (RIA 23) was developed back in the very early 1990s. ‘Formal Proof of Program’ was one of the selected techniques, labelled R for ‘recommended’ (as opposed to HR – ‘Highly Recommended’), for all (Safety Integrity Level) SIL 3 and SIL 4 systems. It was the forerunner to IEC (International Electrotechnical Commission) standard SC65A, concerned with the functional safety of electrical/electronic/programmable electronic systems (which would encompass safety-related software), and the BS EN 50128 standard – Railway applications, communication, signalling and processing systems, software for railway control and protection systems.

The standard has evolved such that formal methods seen today recommend ‘R’ for SIL 1 and 2, and ‘HR’ for SIL 3 and 4. Clearly progress has been made with the standards.

However, there are many preconceptions on what ‘formal methods’ means. One of the more common definitions is ‘Using mathematically rigorous techniques and tools for the specification, design and verification of software and hardware systems’. In the early 1990s, few formal methods existed, with VDM (Vienna Development Method) and the use of Z-notation being two of the options available at the time.

There was good reason for the early standards to only ‘recommend’ formal methods, as they were very much in the early stages of evolution. Not only were they the preserve of academia, but also they were certainly not sufficiently mature to allow industry adoption. Most such methods lacked support for automatic formal proof. It has been a long journey to bring them to the level of sophistication that is available today.

First foray

In 2001, Siemens Rail Automation (which at that time was Invensys Rail) worked with the National Physical Laboratory (NPL) – the distributor of products from Prover Technology in the UK – on formal proof of requirements against an interlocking. In those early days, the safety requirements (the signalling principles) were the preserve of experienced ‘Signalling Engineers’. Written requirements, as we understand and use them today, just did not exist at the time.

This was a major first hurdle. What were thought to be ‘clear requirements’ were, in fact, imprecise. The combination of a lack of understanding of the necessity for precise requirements and the toolset itself caused considerable challenges. The approach was not considered viable for commercial use at the time.

Second foray

Several years later, as a result of a technology change with the Trackguard Westrace Mk I interlocking (configured by means of ladder logic) being replaced by the Mk II interlocking that is in use today, the capacity for configuration data increased ten-fold. With the higher potential for error as a result of increased data capacity, and the opportunity to apply the new technology onto Network Rail infrastructure through modular signalling, both templated design methods and formal methods approaches were investigated.

By this time, the understanding of the necessity for precise requirements had matured and, compared to the early days of the project, tool support had evolved considerably and established a long track record in railway signalling application.

Prover Technology’s standard process for development and Validation & Verification (V&V) of interlocking system software, Prover Trident, is based on using a generic requirement specification library for a particular railway. This library is defined in the PiSPEC language and includes design, test and safety requirements.

Based on the library, the software tool suite Prover iLock™ provides configuration and automatic generation of interlocking data, including simulation and verification and all test cases and safety requirements for the particular location.

Prover Certifier™ is a sign-off verification tool developed in compliance with SIL 4, creating the safety evidence for the location, based on automated formal proof.

Clearly, using a formal approach such as this requires a definition of both the safety strategy and the approach, to gain acceptance with the customer and, internally, with the design and test community.

By this time, the process had evolved from just using formal proof to also including the generation of the data, test of the data and sign-off verification – in other words, complete automation of the process from a data configuration perspective.

The architecture of the system comprises a suite of generic specifications, including the generic rules (design, test and safety), which have a 1:1 relationship with the ‘Signalling Rules’ for a specific infrastructure owner and are only specified once.

Once completed, the next step in the process is the specification of the specific installation, in other words the Scheme Plan. This is either entered in XML (extensible markup language) format, electronically via SDEF (standard data exchange format) as specified by Network Rail, or using other electronic formats, for instance RailML (European open data exchange format).

Once these are in place, the other manual input to the process is defining the input/output mapping that specifies the allocation of function names to mnemonics.

Results of the second foray

Data for the Shrewsbury to Crewe (SYC) Modular Signalling project for Network Rail was prototyped as a single interlocking (today there are three interlockings). A number of iterations of the evolvement of the ‘Safety Requirements’ occurred between Siemens and Prover engineers (configurers of the toolset) but, in concept, the whole process created the interlocking code, test cases, safety requirements and verified and simulated the application in less than 40 minutes once set up. This demonstrated not only the viability of the toolset, but also that any future changes to the layout or signalling principles could be easily changed and rerun in minutes.

Whilst the process of generation and test had been proven by the prototype SYC installation, clearly the safety argument for the tool use was significantly more of a challenge. The basic premise used for the auto-generation and auto-test of the configured data is for a suite of SIL0 applications which, once complete, are presented to the existing Westrace Graphical Configuration System (GCS) toolset (in the same manner as would be used with templates). The application data is then subject to consistency checking, compilation, de-compilation and reverse checking, prior to input to Prover Certifier for sign-off verification.

This process was subject to independent assessment by Professor John McDermid of the University of York, who concluded: “Siemens is to be commended for the strategy it has followed in introducing formal methods into its processes. Formal methods do offer benefits, but they are not a panacea and the approach adopted by Siemens seems to be balanced and to have due attention to the need to demonstrate the integrity of tools on which the process relies, and also to acknowledge the important role of humans in the process.”

Third foray

Subsequently, an opportunity arose to apply Prover Technology to an overseas metro contract. In essence, this encompassed the implementation of the sign-off verification (certification) process only, with the configuration data having already been generated and tested using conventional means. This required a slightly different approach, whilst the definition and review of the safety requirements remained one of the major activities.

The input of the geographical representation of the railway was a minor challenge (this project entered the geographical representation manually). After the third iteration of conventional testing, the forth iteration was tested solely with the toolset.

Lessons learned

The biggest problems faced on any project are imprecise, ambiguous or conflicting requirements. During development of the generic application, requirements need to be presented in natural language so they can easily be translated into the toolset code. This removes ambiguity and forces conflicting requirements to be expanded to a more explicit form so the conflict can be removed. As signalling engineers tend to talk in a language that software engineers don’t understand, this process can be harder than it sounds!

The safety requirements, themselves based upon two previously and successfully implemented projects, still contained some requirements that were imprecise, ambiguous or conflicting. While sufficient for conventional development that relies on principles testers’ knowledge, imprecise requirements raise exceptions when the toolset is run. So, preciseness of requirements is key to successful deployment.

Having a baseline of design, safety and testing requirements for the generic application agreed at the start of the project helps avoid scope creep and minimises changes during the project lifecycle.

The downside to this reliance on the generic application is that getting a project off the ground is labour intensive.

Any missed safety requirements limit the scope of the safety verification.

With a tool-assisted process for development and V&V, much of the V&V and manual steps are automated. This moves the focus to capturing the requirements – traditional V&V has used more ad-hoc verification of interlocking data, not requiring the same level of requirement capture. Therefore, the design, review and checking process of generic application specifications has to be extremely robust.

The tools for formal proof analyse the interlocking logic by only looking at the critical functions defined in the object model, determining whether safety requirements can be broken or not. This is a more economical way of data verification and avoids the complications caused by irrelevant warnings.

Principles testers have a habit of trying to test every contact in a ladder logic rung, resulting in lots of test logs which either question the design or state that they are unable to verify the design due to it being untestable. Using formal proof analysis, the logic can be scrutinised in greater detail, and each safety requirement can be determined to either hold or have a counter example. For example, there have been examples where safety requirements are not met for individual cycles, which is very hard to establish using traditional testing methods.

One of the issues was determining what additional testing evidence was required, over and above the level of verification that was automated by the Prover toolset. This was essential to the process of developing the safety principles, and resulted in a further iteration of the toolset. When the model was initially developed, the primary focus was on the ‘Signalling Principles’, the operation of the overall system and its verification wasn’t fully taken into account.

Overall, this foray has been successful, allowing for future modifications to be verified solely using Prover Certifier and replacing current principles testing for data.

Object models

In parallel to the above, significant work has been undertaken capturing requirements contained within Network Rail’s Modular Signalling Handbook. As previously noted, missing, ambiguous or implied (badly specified) signalling requirements will lead to incomplete specification and thus incomplete proof. So, the importance of requirements capture cannot be emphasised strongly enough.

This led to a comprehensive trawl of, not only the UK Modular Signalling Handbook, but also other existing standards within the Network Rail portfolio (there is significant fragmentation on this subject, and many different documents), to produce a comprehensive object model – one which splits basic interlocking functionality into ‘objects’.

The object model is a central part of the generic application, used within the generic safety specification, generic design specification and generic test specification. Apart from the objects themselves, the object model defines attributes of each object and the relationships to other objects within the model.

The diagram shows an object model – a representation of the characteristics of an auto signal and its relationship and multiplicity with signalling objects. The properties (relationships, static and dynamic attributes) of abstract objects are inherited by their offspring objects, with generic properties defined at the highest possible level in the inheritance tree to avoid repetition.

Adding the definition of the inputs, outputs, dynamic and static attributes (name, control bits and function), the model of the auto signal becomes complete. With all objects modelled, the overall object model can be used to define the design and safety properties for all modular signalling applications.

This was clearly a complex and time-consuming task, with traceability to the existing standards in place and formal review with signalling experts, but did give high confidence of completeness and correctness.

The next task is the derivation of the safety requirements which, based on the natural language requirements and the object model, are defined in terms of the object model to become the ‘formal’ generic safety specification. In combination with the generic design specification, the document that defines the ‘design’ rules, and the generic test specification, the document that defines the ‘test’ rules, these form the ‘Generic’ suite of ‘Requirements’ that input into the toolset.

Prover Certifier is now being implemented in parallel to the traditional well-tried and tested method of creation and test of a specific modular interlocking to be commissioned in the UK. The next step – Generic Use for Modular Signalling?

International implementation

A number of railway infrastructure managers (IMs) today have contract requirements that mandate the use of formal proof for safety verification, prior to commissioning of interlocking and CBTC systems. Examples include Trafikverket in Sweden, RATP on Paris Metro, New York City Transit and Stockholm Metro. There is reason to believe that many other IMs will follow suit as they increasingly demand reduced engineering effort and duration for system delivery – the use of automation tools and sign-off verification of IM requirements are key ingredients to be able to meet this demand.

From a technology point of view, the obstacles are few, if any. The major challenge lies with people and mind-sets. One way to approach this is by the gradual introduction of new tools and processes in production projects, gaining the trust of and educating the signalling engineering experts and IMs involved.

For some, it may be just as well to skip the gradual introduction and directly replace existing processes with automated development and sign-off verification. This is the approach taken by the Class 1 freight railroad Canadian Pacific in North America – there were clear business benefits in introducing automated development with Prover iLock, based on a generic application defining signalling principles.

There are several other examples where such full automation processes are in use in Europe, including at Stockholm Metro.

Assured future

It is clear that the ‘Formal Methods’ seen in the early 1990s have evolved significantly. Formal proof as a means to verify safety has matured to the point that it can be applied for any railway interlocking system. Proof of safety can also be used within automated development processes for railway interlockings.

Siemens has worked in partnership with Prover Technology to demonstrate the worth of these tools in terms of feasibility on both UK infrastructure (generation and test of configuration data on Shrewsbury-Crewe in 40 minutes) and non-UK infrastructure (formal proof only).

There remain many hearts and minds to win over and the journey requires a considerable change in behaviours within the signalling industry. It is more than a concept, there are other signalling suppliers taking this approach, and there are other providers of Formal Methods toolsets on the market, but the tools and processes are here to stay.

This article was written by Pete Duggan, chief engineer at Siemens Rail Automation

 

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