Around 10 years ago, the term Digital Railway came into being. Since then, many articles written in Rail Engineer and elsewhere have covered the topic. But what does it mean and is there any consensus of its objectives and benefits? Getting a consistent definition has proved elusive so in this 200th edition, it is appropriate to look back and see what has been achieved and what has not.
Back to basics
The word digital is bandied about by many organisations and individuals, yet most haven’t a clue as to what it means. In earlier years, systems were analogue which, in broad terms, means that what’s put in at the sending end is essentially the same as what comes at the receiving end. En route, the signal (or information) is subject to distortion and interference, so techniques were successfully used to keep these factors to a minimum. Cables would be screened, often with co-axial tubes, filters removed frequencies outside of the required band, amplifiers increased the transmission level along the way and radio signal levels would be at a transmitted strength high enough for the receivers to produce the necessary quality intelligence. Even early computers worked with analogue inputs and outputs. All of this demanded expensive high-quality equipment with an upper practical limit on the amount of information that could be passed.
Could there be a better way?
So emerged the digital concept. If the analogue signal could be encoded at the transmission point into a series of 0s and 1s, then transmitted to line with the receiver being able to recognise these, the original signal could be recreated without any distortion. The first digital computers emerged in the late 1950s followed by digital communication links, which were vital if computers were to transmit useful data.
Known initially as pulse code modulation (PCM), British Rail had such a system from Euston to Bletchley during the late 1960s. The process first sampled the analogue speech signal at a suitable bit rate and then converted each sample into an 8-bit code. Providing the far end can read this code, no matter how distorted, then the original speech can be reproduced. Low quality cable pairs could be used with periodic regenerators to look at the incoming 0s and 1s and then regenerate them for onward transmission. It proved a great success from which all modern transmission systems with huge bit rates are part of our daily lives. Digital techniques extend way beyond transmission of information but the same basic principles apply.
The Digital Railway
Network Rail’s ‘Digital Railway’ emerged in 2014 with Jerry England as the leader of a project group. An interview with Martin Arter, the programme development director, in 2015, explained the concept. At that time, the many hundreds of computer systems used by the railway covered timetabling, train planning, staff rostering, paybill, accountancy, freight train management (TOPS), and even some elements of signalling with the introduction of computer based interlockings. Many of these originated from the British Rail Information Systems and Technology Group based in Derby, led by the late Otto Benz. These systems tended to be standalone with little integration and limited potential to expand into other applications. An exception was TOPS where its ability to track trains was used for real time train reporting in the system known as TRUST.
Martin spelt out three prime objectives for the digital railway:
- Enabling provision of more trains thus increasing capacity
- Providing better connections between routes and at stations
- Greater convenience for the customer such as ticketing and reservation options, thus moving beyond the magnetic strip.
The digital railway was seen not in terms of technology or engineering but as an instrument for business change. The vision was correct, but it was naïve to not properly recognise the required technological challenges. With only a small team, it was realised that a much more pragmatic approach would be needed if the vision was to be fulfilled.
Enter David Waboso, a seasoned railwayman with a track record of introducing new systems and technology into London Underground to achieve greater line capacity, and who had recently become Network Rail’s capital programmes director. He had the right background to take on the digital railway project. During an interview in late 2016, it became clear that whilst David subscribed to the vision of the team, the priorities needed to be re-assessed. The drive for greater capacity from the existing infrastructure and the need for improved operational performance meant concentrating on ERTMS/ETCS, Traffic Management Systems (TMS) and Driver Advisory Systems (DAS). From these would come intelligent trains, remote condition monitoring, energy supply resilience and more effective recovery from failures.
Business applications like ticketing, passenger information, train loading data and connections to the internet and social media would develop by themselves using industry initiatives applicable to the wider travel audience. These goals would need the full co-operation of the entire industry: Network Rail, TOCs, and the supply chain. Almost by definition, the digital railway projects involved software, a troublesome element in the past, but would rely on properly specifying the functional and operational requirements.
Although progress was made, David decided to retire in early 2019 and reflected in an interview that progress with introducing ETCS was painfully slow, that TMS was proving difficult to implement, whilst DAS was being introduced gradually by train companies. When asked if the digital railway should remain as a separate entity, he concluded that a central advisory team was needed but that the implementation should be devolved to the routes and the TOCs. Integration into mainstream business must eventually happen.
A conference organised by the Railway Industry Association in June 2020 looked at Network Rail’s intention to create a digital railway Technical Authority with six ‘pillars’ making up the group’s focus. These were:
- Network strategy and operations
- Passenger interests
- Freight interests
- Network Rail Telecoms (NRT)
- Operations project delivery
- Signalling innovations including testing and commissioning
The digital railway group would need expanding from 180 people to 1500. Just where these people would come from and how they would be trained was a critical question, but perhaps academia might offer some of the expertise? The supply chain and especially the role of SMEs needed to be geared up into an integrated design and development organisation. Progress with the ECML (East Coast Main Line) ETCS project was noted with many challenges emerging.
This summary shows that the digital railway remained something of an enigma as to what it would contain and how it would be implemented. So much for the digital railway’s ‘public face’ – what has actually happened with the systems being promoted, and have they made the expected progress? Subsequent interviews present an interesting analysis.
Transmission of digital information
Although not officially part of the digital rail programme, but vital to its success, has been the creation of a digital backbone based upon a national fibre cable network instigated initially by BR and subsequently by NR’s telecom subsidiary Network Rail Telecoms (NRT).
Known as the Fixed Telecom Network (FTN), work to create this began in the early 1990s with the provision of a Synchronous Digital Hierarchy (SDH) network borne upon the fibre cables. The main BR centres were connected, with a huge increase in capacity (155.52Mbits) compared to the analogue networks being replaced. Network Rail expanded this project by creating a national team to provide fibre cable to even the most remote parts of the country and it has proved to be a worthwhile investment.
A September 2009 article gave information on Internet Protocol (IP) networking with standards for connecting computers to the internet. This involves every data device having its own IP address from which calls or messages are sent to routers that connect to other routers across the country, and indeed the world. Railway applications were soon recognised embracing speech (VoIP), data (embracing local LANs and WANs), video (for CCTV networking), and radio such as GSM-R.
Local projects within NR were planned but an article in October 2010 described the work done in Scotland to introduce a regional IP network, structured upon spare fibres in the cables to provide a capacity of 1Gbit/sec with a future capability to expand up to 10Gbit/sec. The network had a core layer based on two main rings emanating from Greenhill and Carstairs linking to the main Scottish centres, then two access layer rings drilling down to the main stations and depots around the region and finally local connections on copper cable to station or office devices.
As such, a national IP network was created under the direction of NRT, becoming known as the FTNx. NR recognised the importance of this investment, which provided the opportunity for a multitude of applications, many for business and operational uses but including the safety-related distribution of signalling information and electrification control. With its high resilience coming from a ring structure and round the clock network management, signal engineers and electrification engineers accepted that it was no longer economic or practical to provide their own data distribution infrastructure. Using an all-purpose bearer made perfect sense without compromising the end device safety classification.
So far, so good, but what has been the progress with other new digital applications forming part of the Digital Railway?
ERTMS and ETCS
In Europe and beyond, the need for a standardised signalling control system was apparent if trains were to cross borders seamlessly. So evolved the European Rail Traffic Management System (ERTMS) and its signalling component, European Train Control System (ETCS). The systems would give capacity enhancement and eventually allow the concept of moving block and the reduction of lineside signalling infrastructure. The ongoing progress has been varied, with the Swiss leading the way with a trial operation between Berne and Olten in the early years of this century. Various problems emerged with the software, and it was not until 2016 that a finalised version was signed off.
The UK decided to adopt ERTMS which was first described by Rail Engineer in an April 2005 feature. A two-part article in November and December 2007 explained how ERTMS had three component parts: ETCS, GSM-R, and ETML. A trial system on the Cambrian line was planned but also mentioned were other routes where resignalling was due and where ETCS would be applicable: Peterborough Ely Norwich, Oxford Evesham, Chester Holyhead, and Wolverhampton Chester. None of these have been progressed but some have since been equipped with modular signalling technology.
The Cambrian trial proceeded, made easier by it being a route previously equipped with RETB and no lineside signals, controlled from a centre at Machynlleth. An article in December 2010 recorded the official opening from Pwllheli to Harlech using the newly installed GSM-R radio network to carry the data signals. A further article in May 2011 recounted an IRSE technical visit once the line was fully equipped back to Shrewsbury. Some of the advantages that ETCS would bring were noted, one being the giving of movement authorities to intermediate markers between passing loops thus potentially increasing capacity. However, operational flexibility was restricted by only allowing one train into a passing loop and proved stationary, before a second train could be accepted. Also noted was the high cost of retrofitting the captive fleet of Class 158 DMUs. The project gave valuable experience as to how ETCS would benefit busier lines.
An article in January 2012 looked at the advancement of ETCS across Europe. Whilst it could be easily deployed on new high-speed lines with dedicated train fleets, applying it to existing mixed traffic routes was beset with difficulties unless lineside signals were retained, thus diminishing the business case. Removing lineside signals requires all trains using the route to be equipped with ETCS, which is a major logistical challenge. The limited capability of the GSM-R radio to carry the growing amount of data was also flagged up as something that needed addressing.
The UK needed to fully test the technology and prove the benefits operationally. An article in July 2014 followed a visit to a test site near Hertford using an EMU fitted with ETCS equipment. In addition, a control centre test facility was built at Hitchin and sectioned off so that different manufacturers could install their particular system and prove interoperability with the test train. The site was also used for testing Automatic Train Operation (ATO) as a part of the ETCS package which was subsequently successfully introduced on the Thameslink central core. This site has proved immensely useful but predictions for main line ETCS provision, GW to Bristol by 2018, ECML to Doncaster by 2020, Midland Main Line by 2022, were wildly optimistic.
More realism emerged in our March 2018 edition as to the ECML programme. The route’s operational challenges were outlined with a three-stage programme beginning in 2020, starting at the London end. Special arrangements would be needed at Peterborough to cater for non-fitted trains crossing the city from east to west. ETCS would need training of drivers and a visit to the Kings Cross simulator was described in the November 2016 edition, well before the first rollout programme was released. Designed around the then Class 91 and HST fleets, the system would be adapted for the Azuma trains on order.
A subsequent interview with Toufic Machnouk, the ECML programme manager, was reported in the March/April 2021 edition. By this time, account was taken of new train fleets, the remodelling of Kings Cross station, and the construction of the Werrington dive under. The plan was then estimated to cost £1.8 billion and would take until 2029 for it to reach Stoke Tunnel, just short of Grantham. Since then, the Northern City line from Finsbury Park to Moorgate has been equipped and is under testing but is not expected to be fully operational until 2024.
Clearly, introducing ETCS was going to be a lot more difficult than originally envisaged, not just in the UK but across Europe as well. A September 2015 article revealed that only Denmark, Norway, Switzerland, Belgium, and Austria were intent on nationwide fitment, with Denmark nearly achieving this. Even here, interoperability problems emerged between the two supplier organisations.
The challenge of having ETCS Level 3, whereby virtually all lineside equipment can be removed including track circuits and axle counters plus allowing the adoption of moving block, is ongoing. A joint UK-Netherlands initiative to design a hybrid L3 system was described in the May 2017 edition, whereby one fitted train followed by another fitted train would allow the second train to advance closer to the first using moving block principles. Any unfitted train would have to proceed on the fixed block distances. A trial was intended but no report has emerged that this has happened in the UK or in Europe.
In the UK, only the following routes feature ETCS:
- The Cambrian from Shrewsbury to Aberystwyth and Machynlleth in 2010/11.
- The Thameslink central core from London Bridge to St Pancras with ATO.
- Great Western from Paddington to Heathrow primarily for Elizabeth Line trains, so retaining lineside signals except for the Heathrow branch.
- Northern City Line from Finsbury Park to Moorgate but only in test mode.
- ECML from Kings Cross to Stoke tunnel as a project but not due for full commissioning until 2029.
All new build trains since 2012 have had to be ready for ETCS fitment but, in reality, many of these trains will be life expired before the infrastructure is commissioned. Not the success story that was predicted two decades ago.
Traffic Management Systems (TMS)
The introduction of ETCS, whilst enabling increased capacity, would not be the total solution unless the movement of trains over a large area could be determined. This needs TMS. Network Rail initiated a ‘beauty parade’ of three suppliers who produced proprietary TMS systems with an article in May 2014 explaining this. The three systems were:
- Hitachi Tranista which was in use of the Japanese Shinkansen lines and suburban routes around Tokyo.
- Thales Aramis and linked to the Siemens WestCad platform.
- Alstom Iconis already deployed in the Bologna region of Italy and elsewhere.
All three were asked to model their system around the Leeds area with its multitude of routes and complex station area. TMS would link to other data systems such as train describers, timetable data, train crew scheduling, rolling stock deployment and possession management, and use its intelligence to establish optimum train regulation patterns. Outputs would be given to signallers for the preferred routing of trains, to DAS (see later) giving speed advice to drivers, to Darwin for passenger information displays and on to social media, and to make easy provision for timetabling additional trains into the network.
The result was a contract let to Thales to provide TMS systems at Cardiff and Romford signalling centres. Both struggled to interface with other data systems but were eventually commissioned and used for timetable de-confliction. The system is capable of automatically setting optimised routes to replace earlier Automatic Route Setting (ARS) systems that relied only on timetable data.
A fourth player entered the field in 2018, this being Resonate (ex Delta Rail and a spin off from the former BR Research dept) with its Luminate system that was introduced on the London-Bristol route of the GW main line. With a pedigree of train control and communications system development, this company understood how TMS would fit into existing railway infrastructure and systems. Luminate is deemed a success and has since been deployed on the Anglia route.
The Thameslink route, with its planned 24 trains per hour, was considered to need TMS to regulate trains at the central core entry points of Blackfriars and St Pancras. To be effective, it needed to focus on the converging routes for at least a 20-minute look back of train running data. The Hitachi Tranista system was selected and has been commissioned. The effectiveness of the decision-making capability remains to be declared.
A joint IMechE and IRSE conference in 2018 with an article in the August edition, reminded people that European Traffic Management Level (ETML), the third component of ERTMS, had been overtaken by the development of proprietary systems. Not having TMS as a standard product was becoming a real problem. Whilst TMS remains viewed as a cornerstone for improved rail operations, its full value and how it is implemented nationwide remains a challenge.
Driver Advisory Systems (DAS)
Coupled to both ETCS and TMS is the need to advise drivers of the optimum speed that the train should be driven to avoid deviating from the operational timetable. A Rail Engineer article in June 2013 followed a demonstration of DAS at Didcot Railway Operations Centre. DAS was being deployed by First Great Western (FGW) as onboard standalone devices, programmed with the train characteristics (braking, maximum speed, etc.), the timetable, and the features of the route ahead (gradients, speed restrictions, junction information, stopping points). By connecting to a GPS receiver and a datalink via the GSM public mobile radio, the position of the train and its speed can be constantly monitored. Algorithms then calculate the correct speed for the train to be on time at the next location.
The trains need an onboard processor and a cab-mounted touch screen upon which the advisory speed would be shown. The intention is to avoid junction conflicts and save energy by minimising the need for rapid acceleration and heavy braking. Several TOCs and FOCs have subsequently equipped their rolling stock with DAS equipment, mainly in standalone mode (S-DAS). It must be emphasised that the advice given does not override the reading of lineside signals and, as such, is not safety related.
S-DAS has limitations as it does not take account of other train movements that could impact on the timetabled path of another train. To overcome this, a connected system known as C-DAS is needed. Several companies claim to have such systems by linkage into active timetable databases and train describers which improves the information quality. However, to obtain accurate train running information, a connection to TMS is required. As indicated, the deployment of TMS has its own problems.
One challenge originating from the first applications was the cost and disruption in fitting DAS units into cabs. It cost FGW a sizable amount to equip its main line fleet, so it was an act of faith. To avoid this cost, the idea emerged that DAS information could be incorporated on the screen of the new train radios being fitted. The radio has considerable computing power and seemed an obvious solution. An article describing this appeared in the March 2016 issue, where a trial on the London Norwich route was to be undertaken.
In the early 1990s, Europe decided on the need for a common track-to-train radio system to make border crossings seamless. This resulted in the GSM-R standard. First reported in our October 2008 edition, it explained how the public GSM technology was being adapted for railway purposes to give priority calls, group calls, and a functional numbering system. Primarily intended for speech, the system incorporated a data capability to act as a bearer for ETCS. Being a 2G system, it was recognised that the public networks would soon be advancing to an improved technology giving more capacity and faster speeds.
By 2013, the limitations of GSM-R were being noticed but the introduction of packet switching (GPRS) improved the capacity for passing ETCS data, particularly relevant in high traffic areas. Our April 2013 edition looked at what would replace GSM-R and the need for additional radio spectrum. Any future system would be focussed on data rather than speech calls. Another consideration was whether the railways still needed their own radio infrastructure of base stations and masts or could instead rely on the modernised public mobile networks. Difficult questions, but concluding that GSM-R would need to remain in service until 2025.
Speech remained important, and getting a mobile radio that would easily fit into the restricted space of many cabs was a challenge. The March 2014 issue described how Siemens in Poole was developing a new radio that would fit existing space envelopes. As well as a fixed unit in most cabs, it had to be available in transportable form for use on special trains including steam locomotives. Whilst built for the existing GSM-R network, the radio had to be capable of being upgraded to 4G or 5G, whichever technology was chosen for the successor network.
By 2015, the urgency to decide on what would replace GSM-R led to an international conference looking at the various options. Increased interference in some areas of GSM-R operation was noted as a short-term problem with a range of measures being put forward to combat this. The project Future Railway Mobile Communications System (FRMCS) was established with new standards hoping to be in place by 2018. With 5G technology substantially complete, it seemed that FRMCS would be adopting that standard for future track to train radio. A report in the January 2019 edition, noted that the Union Internationale des Chemins de Fer (UIC) – the international union of railways, based in Paris – was developing a functional specification. With the technology decided, the question of how to migrate from GSM-R was seen as a big problem. Industry guarantees were given that GSM-R would be supported until 2030, only a decade away.
FRMCS would offer much more than just speech and an ETCS bearer. The need to provide radio services to the railway business and the travelling public was crucial and additional spectrum would be needed over and above the 4MHz allocated for GSM-R, probably in the 1900-1920MHz or 2.6GHz bands. Additional lineside base stations and masts would be required. The infrastructure would need to be duplicated to allow both GSM-R and FRMCS operation for a significant period of time. On the trains, whilst the new mobiles will need modifications for the 5G upgrade, additional aerials will need fitting to the train roofs plus associated wiring. It was suggested that it should be a franchise requirement to enable this work to begin.
Whilst not formerly seen as part of the digital railway, radio becomes a crucial bearer of data akin to the transmission networks.
Electrification systems in the UK, be they 25kV overhead or 750v third rail, need a system to connect the Control Rooms to the feeder stations, sub stations, track sectioning cabins, and such like. Thirteen Electrification Control Rooms (ECRs) existed nationwide with various proprietary links to the outstations. The December 2015 edition outlined a project to build a new national Supervisory Control and Data Acquisition (SCADA) network that would replace the existing ECRs and integrate electrical control into the Railway Operating Centres (ROCs) then emerging. A contract was let with Telent but progress has been slow and is still ongoing.
The system is borne upon the FTNx using IP addressing, with two data centres to ensure resilience, each linking to the existing ECR sites if the ROC for the area is not yet commissioned. Much improved safety and security is built in compared to the former arrangement and would allow control of the electrified railway to be transferred to another site should an ECR location be disabled. To date, some ECRs still remain, and the project is running late and over budget.
Ticketing, reservations, and barrier control
In line with the wider travel industry, buying tickets and reservations online is something of a minefield in order to get the best deals. Trainline and My Train Ticket are typical sites that give train and fare information. The TOCs also offer ticketing services for their particular routes. Finding the optimum ticket for your journey can be laborious. Tickets are now available to load on to a smart phone and a growing percentage of travellers use this facility. Paper tickets will remain into the future as there will always be people, particularly the elderly, who prefer to have something physical in their hand. Nonetheless this is all part of the digital progression.
At all but rural stations, it is normal to go through a gate line before boarding the train. At peak times or if the train is late in being made ready for departure, there can be a considerable crowd to get through the barriers. This is a slow process as the ticket has to pass through or the smartphone screen be read and checked by the reader. Delay is caused if the ticket is not recognised by the system and recourse to a manual ticket check has to happen.
To speed things up, an article in our April 2017 issue, described an RSSB initiative to automatically link passengers with a smartphone ticket to the barrier being approached using a Bluetooth connection, thus eliminating any physical action. Two companies were developing trials: firstly Bytetoken, now a subsidiary of Siemens Mobility and secondly Thales Revenue Collection Systems. With barriers close together, restricting the information to a single barrier and not those adjacent, needed the precision of the Bluetooth location to be improved possibly by using a 3D camera.
The November 2019 edition reported that the system had been refined and branded as Air Gate. Infrared technology determines whether a passenger has a Bluetooth device and if not, they will be directed to a different set of barriers. The goal is to achieve a barrier transit time of 1 second as against 2.3 seconds for a traditional ticket check, which would be a significant time saving. Trials were predicted but no information can be found as to whether these progressed.
Real-time train reporting
Easier train travel booking is certainly being achieved. However, it is equally important to update travellers on how the services are running both before the journey and during it. This calls for real-time information being extracted from various Network Rail sources and distributed via the internet. Various systems have emerged to offer online services that passengers can access on their smartphones. Real Time Trains and Open Train Times (OTT) are two of them and an article in the April 2020 edition explained how the latter worked. To proceed, this needed Network Rail to grant permission to access their databases. The four main ones are:
- TPS (Train Planning System) to give timetable data.
- TRUST (Train reporting using system TOPS) to give real time running data at specific reporting points.
- TD (Train Describer) to get train movement data direct from signalling centres.
- VSTP (Very Short Term Planning) which yields short term amended timetable data.
From these, live track diagrams are produced and displayed on screen with train descriptions shown according to where trains actually are. The amount of data is enormous – about 7.25 million TD steps and 5250 train movements each day. Trains are displayed as the 4-digit head code so users have to be savvy in learning what the head codes represent but its usefulness is appreciated.
Another early digital railway was Darwin, used to compile greater accuracy in train running data before putting this out on to display screens at stations. The system receives the same type of inputs as for OTT and then assesses how any late running will impact on the service and predict time on station displays. Rail Engineer reported this in September 2011, but since then the system has expanded considerably and the data is even made available for some onboard train information displays.
Progressing a Digital Railway over 10 years and more has made for an interesting review. In broad terms it can be split into two elements:
- Specific projects directed at improving railway operations and capacity gains.
- Business projects to give better information and services to passengers much akin to trends in the general travel trade.
Both of these need an effective and reliable bearer backbone and in this the FTN transmission networks and the GSM-R radio network (soon to be updated) are a big success. Business projects have progressed well and online services are commonplace with daily usage measured in the millions. The general public is much better informed about rail travel than it has ever been.
For the specific operational projects, the progress is mixed. Certainly, DAS is used by ever increasing numbers of TOCs. TMS is slowly rolling out across more routes. A lack of standardisation is foreseen as a problem. The electrification SCADA control network is achieving its objectives and will be even more effective once all the Railway Operating Centres (ROCs) are fully operational.
The big concern is the roll out of ERTMS and ETCS. Progress is painfully slow and it will be decades before even all the main lines are equipped. Is the system too complex and too expensive? Is enough use being made of cross acceptance practices with other European Railways to shorten the safety approval time and enable best practice? The benefits of more capacity and much less lineside equipment are there to be had but it will take years before these are realised. Fortunately, the UK has the Train Protection and Warning System (TPWS) that gives much improved train protection. Ways of updating and expanding TPWS to give some of the benefits of ETCS are being considered with trials expected shortly.
Does the Digital Railway still justify a separate banner? Unlikely, as David Waboso predicted, digital techniques and systems are becoming just part of the normal railway.