Sub Surface Renaissance

9th November 2011

Considerable publicity has already emerged on the new S stock trains being delivered to the Metropolitan Line.

However, these are only part of a massive overall programme to upgrade all of London Underground’s sub surface lines. With a variety of ageing rolling stock, and some signalling systems that date back to the 1940s, the lines are overdue for modernisation.

Hedley Calderbank is the Upgrade Sponsor within London Underground (LU) to ensure that the project plans are financially on course to deliver all the required benefits to LU’s business.

He gave the rail engineer a fascinating insight into the project, its planning and delivery.

The business plan

In the PPP era, the two organisations awarded the contracts were required to put forward plans for major improvement works. Metronet, responsible for the Sub Surface Railway (SSR), was committed to a complete upgrade of trains and signalling on all those routes as a single project.

The existing track layouts had been unchanged for years – some even dated back to the loco hauled days of the Metropolitan Railway. Piecemeal renewals had kept everything largely unchanged as this had been the simplest thing to do.

As a result, many track layouts were less than optimised for the existing train service while the capabilities of both signalling and rolling stock fell well short of LU’s aspirations for capturing more traffic.

The PPP organisational structure has been overtaken by events, but it was the catalyst for developing the SSR scheme as a single entity embracing the Metropolitan, District, Circle and Hammersmith & City lines.

The ensuing business case for the upgrade has been based around a number of elements:

Shorter journey times for passengers – entry gate to exit gate
Faster trains with better acceleration
Provision of more frequent trains, thus giving less waiting time on station platforms
Higher speeds on the Metropolitan line out in the north-west suburbs
Fulfilment of suppressed demand because of existing service limitations

Considerable work has gone into proving that the business case is robust. The peak number of trains per hour on every route will be increased as follows:

Metropolitan Line – from 21 to 28
Circle and Hammersmith & City (central section) – from 28 to 32
District (central section) – from 28 to 32
Hammersmith & City – from 7 to 16, already partially achieved by the extended Circle line
District Line branches – by 1 train on each

Many of these additions are interdependent but, once the existing signalling has been replaced, the peak passenger capacity of the network will be increased by more than 30%.

Layout constrictions and improvements

The SSR group of lines has four major junctions where little can be done to eliminate flat crossings: Aldgate, Baker Street, Edgware Road and Earls Court.

To provide grade-separated layouts would be prohibitively expensive. However, running more trains across the conflicting paths can be simplified by changes to the track layouts, the signalling system and the use of ATR (Automatic Train Regulation).

One example is the Metropolitan line at Baker Street which has two through platforms and two terminating bays. The new service envisages 28 trains per hour with 12 terminating and 16 running onto the Circle line.

This can be achieved by minor adjustments to the track layouts and by changing the signalling to give better ‘run in’ times to platforms so that over restrictive overlaps are removed.

Elsewhere, there are around 30 locations where even minor changes to the layout can give improved operating flexibility and/or higher speeds, as well as providing the opportunity to terminate trains at additional stations.

Some of those locations will have new trackwork with fewer point ends and thus cheaper signalling and less maintenance. Bi-directional signalling enhances these simplifications at some sites.

LUL1 — Installing a Bailey Bridge at Neasden for construction traffic access. Photo: the rail engineer.

The Signalling Work and Contract

As important as the provision of the new trains is the resignalling of the entire SSR network with a modern Automatic Train Control (ATC) system.

The signalling work contract has recently been let to Bombardier for a value of around £350m based upon their CITYFLO 650 product which has been proven on the Metro de Madrid and the Shenzhen Metro.

The terms and conditions for implementation are predictably quite onerous. For the first time on LU, there will be no major blockades permitted for signalling installation, testing or commissioning, although some closures will, of course, be needed for trackwork changes.

The ATC system will first be tested and proven by Bombardier on the Old Dalby test track in the East Midlands. This is planned for 2012/3. Thereafter the new lineside signalling equipment will be progressively installed with the intention of testing it in traffic while in shadow mode.

It will be switched to be live during engineering hours to enable testing to be carried out, but switched back to the old system ready for traffic the next day. The system will have all the features one would expect of a modern metro:

Automatic Train Protection – continuous with elimination of train stops
Moving Block, allowing variable headways
Attended Automatic Train Operation retaining the driver in leading cab
In-cab display showing movement authority status and no lineside signals
Automatic Train Regulation with junction optimisation

Lineside equipment is much reduced with most of the active equipment on board the train. Space was designed into the rolling stock design for the new signalling equipment.

However, as some new trains have already been delivered, these will need to be retro-fitted as will the engineering fleet. Later builds of the trains will have the in-cab signalling fitted as original equipment at the Derby factory.

The new Service Control Centre has already been built. A second disaster recovery centre will also be provided in due course. All communication to and from trains will be by radio which will use conventional aerials on the overground sections.

However, radiating cable will be needed at some locations in tunnels where antenna mounting is not possible. It is intended that a dual transmission path will exist continuously to all trains, resulting in an extremely robust communication system.

To achieve this, both cab units on the train will be active and will receive radio data by independent paths. The cab units will be connected together via an on-train fibre link.

A new fibre network will be installed to convey safety critical instructions to the trackside transmitting points.

Train position will be confirmed by small track-mounted balises. Axle counters will be used for secondary detection only. They will not be needed under normal operation but, should disruption occur, then they will be part of the recovery process.

Point machines of varying types – pneumatic and electrical – will remain where the layout is unaltered, but for new trackwork LU will standardise on a modern in-bearer clamplock design on ballasted track and the Surelock point mechanism elsewhere.

Since station dwell times will be critical in achieving service performance, the driver will have responsibility for door closing, aided by an in-cab countdown clock.

LUL2 — Track relaying. Photo: the rail engineer.

Interfaces with other lines

The Metropolitan and District lines share tracks with the Piccadilly line from Rayners Lane to Uxbridge and Barons Court to Acton.

The District line operates over Network Rail tracks to Wimbledon and Richmond while the Metropolitan line has to accommodate Chiltern Railways trains over its tracks from Harrow to Amersham.

Different philosophies are being employed to cater for the continued safe operation of these “alien” train services.

On the Piccadilly line sections, studies have shown that it is more cost effective to equip the trains with the new SSR ATC equipment rather than to provide dual ATC and lineside signals.

This will also allow interoperability of tracks between Barons Court and Acton so permitting both District and Piccadilly trains to run on either track.

The full ATC system will be provided on the Wimbledon branch from Putney Bridge to Wimbledon in addition to the legacy lineside signalling for the few non-LU trains.

From Gunnersbury to Richmond, the ATC system will be overlaid on the existing conventional Network Rail signalling. On the Chiltern line, there will be lineside signals in parallel with the full ATC system for Marylebone to Aylesbury trains.

Provision may need to be made at Watford for the extension of the line to Watford Junction under the Croxley Link scheme now under active consideration by Hertfordshire County Council.

Should the project come about, this will mean another interface with Network Rail signalling at Watford High Street.

The Chesham branch will remain ‘One Train Working’ but the junction will be moved northwards from Chalfont & Latimer to gain greater capacity.

LUL3 — New S stock train on the Metropolitan line. Photo: the rail engineer.

Project Phasing and Priorities

8-car S stock trains are already entering service on the Metropolitan line and deliveries will be complete by 2013. These will take over from the A stock that has been in service since 1960 and are LU’s oldest trains.

The new trains have, however, necessitated some adjustments to the existing signalling to cater for slightly longer cars, a different driving position and altered signal sighting.

Before the new ATC signalling can be brought into public service use, all trains on a particular route must be operated solely by the new stock.

New signalling can then be commissioned on the Uxbridge branch and then progressively on the rest of the Metropolitan line by 2016, although not at that stage from Baker Street to Aldgate.

Similarly, on the Circle, Hammersmith & City and District lines, which will all receive 7-car S stock sets, the existing signalling will be modified so that trains can be driven for a period in manual mode.

S stock deliveries will be complete in 2016 whereupon the new signalling will be commissioned on the Circle and Hammersmith & City routes, with the District line finally being converted by 2018.

The complexities of this project should not be underestimated. It will be considerably more difficult to achieve than the recent Victoria and Jubilee line upgrades as these were essentially end-to-end routes with no intermediate junctions.

There will no doubt be issues surrounding the required safety case, although a measure of cross acceptance will be applicable as the technology has successfully been applied elsewhere.

To facilitate this, LU has every intention of not deviating from the standard signalling product even if this means changing its operating rules.

It is going to be fascinating over the next seven years to watch the work as it progresses.

The end result will be a world class metro operation that should be good for an intended life of 40 years.

The future’s bright, the future’s ATWS

31st October 2011

For over ten years, Track Warning Systems have been hyped as a track safety and productivity solution. The reality was minimal use and failed pilot schemes. Automatic Track Warning System (ATWS) installations at 17 key locations in 2002 were soon removed.

The Track 02 system lost its safety approval in 2004 after over a hundred sets had been purchased by Network Rail’s Contractors.

Now times are a changing with Network Rail’s successful large scale LOWS (Lookout Operated Warning System) initiative.

Does this mean a brighter future for Track Warning Systems? With the next generation of ATWS under development, and the McNulty report requiring the adoption of more efficient continental practices, it would seem so. The rail engineer visited ATWS suppliers Zöllner and Schweizer to learn more.

Large scale LOWS use

Zöllner’s Frank Peters states that 230 portable LOWS kits have been supplied to Network Rail’s maintenance teams over the past two years. He knows this equipment is intensively used as Zöllner has been closely involved in its introduction by providing training, a hotline, servicing, repair and annual recalibration.

Frank commented: “Initially we were called out quite a bit, but less so now, as depots get used to the kit.”

Network Rail’s standard NR/L3/MTC/SE0206 “Introduction and Management of LOWS Equipment” specifies the competence for its use and the support to be provided by Infrastructure Maintenance Delivery Managers (IMDMs).

This includes the need to map locations to establish a pre-determined Safe System of Work (SSoW) and to confirm radio coverage.

Training is the same for a LOWS Controller and a LOWS Lookout. LOWS competence is deemed to have lapsed if it is not used within 28 days of initial training. Thereafter LOWS must be used at least 10 times in the next three months and once every three months after that.

Network Rail’s successful LOWS implementation is due to the work of the Track Warning Systems (TWS) Steering Group and those in the maintenance organisation who have driven its introduction. Some depots immediately saw its benefits and made more use of LOWS than others.

No doubt the use of LOWS will increase as, with large scale use, its benefits become clear to all. The time to set up and test a LOWS SSoW is very similar to that for a conventional lookout.

Zöllner consider that by far the greatest use of LOWS is for mobile patrolling. LOWS lookouts remain static but can leapfrog each other as the patrol moves in accordance with the pre-determined SSoW determined by the mapping exercise.

Previously, it was often not practicable for mobile Lookouts to maintain the required sighting distance and mobile workgroups accounted for a large percentage of track fatalities so mobile LOWS use offers a significant safety benefit.

Other advantages are that, at night and in fog, there is no need to impose a 20 mph TSR as the LOWS Lookout can be positioned where the train passes. Also the LOWS Lookout need not be on the rail infrastructure. For example a bridge over a steep cutting offers improved radio coverage, increased sighting distance and a less hazardous situation.

The status quo, our greatest competition

Although both Schweizer and Zöllner supply Track Warning Systems, Schweizer’s Chris Foreman feels that his “greatest competitor is the status quo”. On the Swiss rail network, which is less than a quarter the UK network, he estimates the use of ATWS to be between 50 and 100 per day. Both Chris and Frank estimate that ATWS use in the UK is 5 to 10 per day.

Chris clearly believes large scale use of ATWS would benefit the UK rail industry but feels that current arrangements do not provide sufficient incentive for its use as “Programme Managers have to pay for ATWS but do not get the financial benefit from engineering access savings”.

Chris Foreman considers that the McNulty report’s benchmarking UK rail against European practice should drive increased use of ATWS. Frank Peters thinks that it’s odd that, although the RIMINI standard requires ATWS to be the first consideration for Red Zone working, its use is a tiny percentage of Red Zone working. He also feels that ATWS use needs to be considered earlier in project planning.

Unlike LOWS, ATWS automatically detects trains by rail mounted treadles or sensors. It therefore has a higher safety integrity level with manpower savings, particularly at junctions.

The system consists of detection, processing and warning modules that can be connected by either radio or cables. Although radio offers quicker set up times, radio equipment is more expensive than cables and requires batteries to be changed daily.

Both Schweizer and Zöllner supply equipment to companies who offer ATWS solutions. Schweizer supply their Minimel 95 equipment to McGinley and Rail Safety Solutions and Zöllner supply their Autoprowa equipment to Vital Rail and Rail Safety Solutions.

ATWS works well at sites of a long duration. Schweizer’s system was used during BIRSE’s construction work at Southend Airport station where ATWS facilitated access to speed up the project.

Zöllner ATWS equipment on the Forth Bridge minimised the risk to trains by warning Balfour Beatty’s scaffolders to ensure items are secure as trains pass underneath them.

TrackSafety1 — Zollner control unit. Photo: the rail engineer.

The Next Generation

Both Schweizer and Zöllner are about to launch their next generation Track Warning Systems onto the UK market and expect to get product approval soon.

When approved, both of these systems will have new methods of installing train detection treadles enabling them be set-up in about 5 minutes (i.e. between individual trains) as well as bi-directional radio, to provide the LOWS Lookout with confirmation of the warning on site, and movement detection as a deadman’s safety device. They also use less energy and so are lighter than previous systems.

These improvements will give Schweitzer a fully portable LOWS system. Zöllner’s new system uses a Lithium Battery with its own charge indicator and with an optional increased maximum warning sound to 120dB.

Usually the warning will be less than this as Zöllner’s Autoprowa system has microphones to ensure that the warning is appropriate to the ambient noise level. Schweizer will have repeaters to ensure signal strength.

Both these systems have been already been approved in Europe by independent safety assessors, Technischer Überwachungs-Verin (TÜV).

Frank Peters feels that in recent years Network Rail’s “acceptance process is now more professional” and now recognises TÜV technical approval so that product acceptace primarily concerns integration with UK methods of working.

One of the features of the new Zöllner and Schweizer equipment is that it will no longer be necessary for each control unit to be individually manned.

As a result long worksites need only have one LOWS controller. Frank advises that Amey Colas are keen to use this new equipment so that LOWS can provide warnings to staff on the open line adjacent to their High Output track renewals sites.

Controlling the risk to trains from engineering work

ATWS equipment can be used as part of a safe system of work to protect trains from engineering work, as illustrated by the Forth Bridge example. Chris Foreman advises that Schweizer are developing a system to control the risk to trains on the adjacent open line from machines working in an adjacent possession, enabling such lines to be kept open.

This is based on a 2004 pilot scheme which used ATWS equipment to warn machine operators of approaching trains. When it was then confirmed that machines were not foul of the open line, warning detonators were removed from the line.

This method of working was subsequently included in the Rule Book. While similar, Schweizer’s new system uses an emergency red light and temporary TPWS loop to stop trains unless there is confirmation that the line is not fouled by machines.

Using signalling system to detect trains

Using the signalling system to activate a track warning trains offers instant set up times and reduced costs associated with train detection. It also reduces unnecessary warning as, unlike ATWS, the signalling system takes account of the position of points and trains being stopped at signals.

In the UK, use of the signalling system to provide track warning is confined to small scale use of TOWS (Train Operated Warning Systems) on plain line track, in contrast to more sophisticated systems employed in Europe.

In Switzerland, Signal Controlled Warning Systems (SCWS) have been in use for 15 years. SCWS uses processor modules which, with one exception, take a read-only feed from the signalling system to provide a warning for a section of track within the signalling area.

The exception is the need to delay a signal being cleared to provide adequate warning time. The SCWS systems for the track concerned are generally activated on request by, for example a switch, a radio key or detection of a warning module being plugged in. At some locations the length of the warning module’s cable is the length of track for which protection is provided.

Chris Foreman believes that Schweizer’s SCWS could offer significant benefits especially at busy junctions. These are due to reductions in the number of lookouts, and increased working time by eliminating unnecessary warnings from trains approaching the junction which don’t go through the worksite.

Signalling schemes that install bi-directional working and for which additional track staff protection is required, are a further application. Chris feels it should be relatively straightforward to install SCWS in the UK, especially if initial product approval was confined to a read-only feed from the signalling system.

The Austrian version of SCWS uses the GSM-R infrastructure to receive requests for track warnings and activate warning modules. Frank Peters advises that this project has been under development for ten years and saw its first pilot application this year.

It quickly establishes warning systems for any type of worksite, has no radio reception issues and largely eliminates lineside cabling for warning systems. It is however a long term solution. A more immediate option is the use of GSM-R for track warning systems to eliminate the effects of radio black spots.

A new dawn

For ten years, UK use of track warning systems has been minimal. A new dawn is now breaking with Network Rail’s LOWS use solving the problem of mobile patrolling with significant safety and productivity benefits. Although there is still a resistance to the use of automatic train detection, this must surely change with McNulty’s challenge to improve the productivity of engineering access by learning, in part, from European railways .

The difficulties of introducing automatic systems, including detection by the signalling system, should not be underestimated as many factors reinforce the status quo. Tackling this includes the need for cultural change, gaining workforce confidence, product approval and appropriate contractual incentives.

The signs are that Network Rail now has both the commitment and ability to meet this challenge for which its large scale use of LOWS should provide a springboard. Schweizer and Zöllner are also key players who can provide European proven equipment to ensure that soon the status quo will no longer be a serious competitor.

For further information on Network Rail’s Innovation Process and to submit new Track Warning System proposals click here.

MacroRail 2011

31st October 2011

The Railway Storage facility at Long Marston, south of Stratford upon Avon, was host to the recent MacroRail 2011 Exhibition.

For the first time, some 60 Rail Alliance Members gathered together to display their products both on track and in a live rail facility. The rail engineer went along to have a look.

At the entrance to the site, various road-rail vehicles were being unloaded from their trailers. The logos of Keltbray, Trackwork, UCA, JCB and Motorail Logistics were much in evidence.

Three Keltbray Road Rail Vehicles and a Mini Tamper from Trackwork were offloaded from their low loaders onto the track just as they would at a possession access point.

Three areas

The show was split into 3 distinct areas; infrastructure plant, depot maintenance and rolling stock components and services.

With plenty of space available, and members not having to pay to exhibit, it was refreshing to see that companies were able to spread themselves out and display their product ranges properly as opposed to cramming what they could into a 3m x 3m space.

Most of the infrastructure plant was on several sidings, while the components suppliers and some of the more delicate equipment were tucked away indoors in one of the larger hangers on the site.

Just inside the doors of the hanger was KOREC, specialist in the provision of construction, mapping, machine control and rail survey solutions for the rail industry.

It used the space offered at MacroRail to showcase Trimble’s GEDO CE Track Measurement Device, a multi-function, highly accurate track measuring device which, together with field and office software, is approved by Network Rail for use on all of its infrastructure.

However the undoubted star of the KOREC show was the SenseFly SwingletCAM, an unmanned flying camera for aerial mapping projects which can be launched by hand and weighs less than 500g. KOREC’s Andrew Blogg made full use of an outside demonstration area to show just how quickly and easily the SwingletCAM can be launched – it certainly brought the spectators’ cameras out!

Recently trialled successfully by Costain on the M1 with a view to speeding up their planning and progress reporting process, the Swinglet CAM would be ideal for use in the rail sector for applications such as route planning and checking track-side vegetation.

KOREC were only one of several exhibitors taking advantage of Long Marston’s open spaces to show their products off outside. Close by, Arc-Gen Hilta was demonstrating its Weldmaker along with ESAB’s Railtrack welding unit.

The Network Rail approved lightweight portable generators were remarkably quiet while the automated welder sparked into action and provided a smooth accurate weld in next to no time.

In the depot area, Motorail Logistics’ road-rail shunter resembled a giant JCB tractor with buffers. It is based on a JCB power platform but weighs in at a fraction of the price of traditional shunting vehicles while offering the flexibility of being able to be used off track as well.

Inside the hall

Back in the hanger, Sheffield-based Zonegreen had brought along a brand-new automated remote control system which allows maintenance depots and sidings to operate manual points from the vehicle without having to leave the cab.

Also of interest to depot operators was Autodrain, which was exhibiting an oil drainage pump that is currently installed at the Hitachi Depot in Ashford, Kent. The company also designs and manufactures a product called Oil Away.

This pumps hot oil straight from the engine sump into a storage tank. Leak-free twist connections to the sump mean fewer oil spills in the workshops and prevent any burns from hot oil to maintenance operatives.

Bratts Ladders of Nottingham was demonstrating various access platforms and ladders which were made out of glass fibre which are already being used in depots and heritage maintenance yards for accessing rolling stock safely.

Visitors watched as Bratts’ personnel erected a lightweight Teletower to a height of 4 meters in a few minutes. Even more impressively, they dismantled it again, folded it up, and fitted it into the back of an estate car.

Achilles showcased Link-up, the rail industry supplier registration and qualification scheme, which is used extensively by procurement, engineering, safety and quality professionals. Approximately 2,700 individual users currently have access to Link-up information on existing and potential suppliers to aid them with their procurement activities.

Back outside

Outside again, and Trackwork were demonstrating their mini-tamper on a 200 metre run of siding. This road-rail Plasser & Theurer 08 Tamper, which at only 7 metres long, can turn itself round on its own axis. After a 200 metre run it simply jacked itself up, spun around through 180 degrees, and proceeded to carry out another run.

Keltbray’s three road-railers, which had earlier been seen at the entrance, were up now also in the sidings. A tracked Komatsu P228, fitted with a Movax SP50-W vibratory piling hammer, was demonstrating picking up tubular steel pile then starting to drive it into the ground.

A second P228, this one with a Fambo piling hammer, finished the job off. The Movax then pulled the pile back out again, ready for the next demonstration to start.

Alongside all this noisy action was Keltbray’s one-of-a-kind Mani-Railer. Recently used to erect communications masts and a variety of maintenance operations from Bedford to Chichester, the RRV is capable of lifting to 17 metres with a load of five tonnes.

The platform, which is controllable from the basket or from the base vehicle, can extend out and underneath a bridge to remove the need for scaffolding or rope access while surveying.

Transformers and seats

Chesterfield based Trans-Tronic, who acquired Tesla Transformers and EMDEC in 2009, have continued to expand into the railway industry. The signalling, transformer and rectifier manufacturer was displaying a range of coil windings and toroidal transformers.

For stations, Eglin Concourse International exhibited their range of public waiting area seating including an external DDA compliant platform seat unit, a wall mounted perch unit and a polished stainless steel seat unit with upholstery pads suitable for internal waiting areas.

Eglin have recently added a new Iroko wooden bench unit to the seating range and this was also on display.

Made in Britain

Manufacturing is alive and well amongst Rail Alliance members. Several firms inside the hall represented the British manufacturing rolling stock component sector.

Glass specialist Independent Glass were displaying toughened, laminated and laminated toughened glass compliant to the BS857 Kite Mark. Stare out of any window on a UK train and the chances are you are looking through Independent Glass.

You may also find their products in the doors, internal draught screens, luggage racks and the mirrors in bathrooms on trains throughout the UK.

The glass specialist was a major contributor to the safety standards set in the UK and have a purpose built test rig where they test the glass to the latest GM/RT 2100 Issue 4:2011 test standards.

Worcester based Southco were displaying their security latches, locks, electronic access and positioning controls. Representatives asserted that, no matter how much vibration there was on a train, if there was a Southco product holding it closed there was no way the vibration would open the lock.

Avdel were promoting their blind fastening locking bolt system for fixing to a component where you only have one sided access. The Welwyn Garden city based business is celebrating its 75th anniversary this year.

All in all, a wide range of Rail Alliance members were represented, 61 in all out of a total membership of over 200. Regular contributors to the rail engineer were amongst them, including telecommunications network specialist Westermo, Visul Systems with its range of tactile strips and tiles for stations, York EMC who showed how to check for EMC emissions for trains and lineside equipment, and Rockwell Automation.

TQ Catalis talked about training, Hall Rail about switches and crossings, Wor-Rail about Nencki lifting equipment, and Vital Rail about security. ACO Technologies were the people to see of you were interested in water management and drainage, and MIRA was there if you wanted to crash test your train!

Positive verdict

Robert Hopkin, Executive Director of the Rail Alliance, reflected on the success of MacroRail 2011.

“We are delighted that so many of our members have taken this opportunity to take space here,” he commented.

“Our aim for this inaugural event was to prove the concept can work, with the Rail Alliance taking the financial risk in staging this year’s event. Importantly, we have felt for some time that, whilst the major exhibitions have their place and provide their own value to exhibitors, we also see that there is a requirement for a ‘no-frills’ opportunity for companies to exhibit their products and services in a rail environment and this is why we developed the MacroRail concept.

“Another feature of the event, and this is more of a reflection of the diverse nature of our membership than anything else, has been the opportunity for our members to indulge in a bit of what we call “Four Walls Working” whereby business opportunities between members can be discussed and debated, person-to-person, with the equipment right in front of them.

“We had several reports of members re-establishing or establishing contacts and sowing the seeds for possible partnering or collaborative projects in the future.

“The overriding comment from the exhibitors I talked to was that the quality of the visitors was high – and this is exactly what we set out to do, to stage a Low Cost / High Value event in the interests of our members.”

There were over 140 members who didn’t exhibit at MacroRail 2011 – the 2012 event can only be bigger and better.

A new tool in the box

31st October 2011

The rail industry is increasingly being challenged to improve the management and extend the life of one of its basic and most expensive assets, the rails themselves.

This challenge is being met by a better understanding of rail metallurgy, lubrication, profiles and direct intervention through material removal. Of these, the latter has seen the development of the rail grinding machine from the earliest days of converted trams to modern, purpose-built trains.

Rail management

The benefits of rail management through rail grinding have long been recognised in the world-wide rail industry. In the UK, as economics, regulatory and safety issues have come more to the forefront over recent years, the technology has seen a steady increase in application.

Grinding, though, has its limitations, risks and environmental issues. It cannot be used in some tunnels or high fire risk areas, it has trouble dealing effectively with heavy rail damage, and much of its waste product remains on the track. So, after some 100 years of rail grinding, it is time to find a new tool in the toolbox.

The rail miller offers a more environmentally-effective method of rail management with an ability to do in one pass something that a rail grinder cannot do in many, if at all.

Most importantly, for many modern signalling and traction systems, milling does not leave its waste product behind on the track. Instead, it is recovered back inside the machine so it can be disposed of safely

An accepted technology

Rail milling has been covered in the rail engineer before, most recently in issue 69 (July 2010). The technology has become accepted in Europe and the Far-East, with investment in machines both by rail operators and contractors.

STRABAG Rail is at the forefront of this new technology and has invested heavily in it. A major service supplier to rail organisations around Europe, the company has a wide ranging fleet of rail maintenance machines to which it is now adding four rail milling machines, two rail-road and two track-based units, for a total investment of more than €100 million.

It has even had one of the rail-road machines specially converted for use on the British loading gauge. STRABAG Rail brought that unit over during 2010 and, having passed the requirements for operation on the Docklands Light Railway, it undertook some trial work which saw it complete some 9600 metres during six shifts of trouble-free track milling, producing 4100 metres of finished track allowing for areas of severe damage which required two or three passes.

Various representatives of Network Rail and London Underground saw the rail miller in operation, and were keen to try it on their own networks as soon as was practical. A return visit has been arranged for late in 2011.

Consistency

One key advantage of the rail miller is that the finished rail profile is built into the cutting head. This is manufactured with renewable cutter teeth so that there is no possibility of inconsistency in the profile finish.

While the milling leaves small facets, around the size of a thumbnail, on the rail head these are easily removed by a tangential grinding wheel positioned just behind the milling head which leaves a finished roughness of 3-4µmm.

This is perfect for visual, ultrasonic or measurement inspection to ensure that defects have been removed, and that the desired profile has been achieved.

Environmental advantages

The design of the milling head unit and the patented grinding finish system ensures that both the swarf generated in milling and dust from the grinding are 99% recovered by a process that a conventional rail grinder cannot match.

So there is little or no residual waste left on the track to contaminate rolling stock and the track bed, especially significant for points equipment and track circuits. Recovered swarf can be recycled whilst the dust may be disposed of in a controlled manner.

The milling process, with a single final grinding pass, is also significantly quieter than a conventional rail grinder while, to the casual observer, it does not look like a mobile firework display, which can be a bit startling!

The lack of ‘fireworks’ also means that there is a very low fire risk arising from the milling process due to the enclosed nature of the grinding head and its spark containment. London Underground has been particularly interested in this aspect of rail milling.

Operation

STRABAG Rail’s rail-road milling machine is impressive in its appearance and design and offers the flexibility of being available to a range of operators as it can easily transfer from location to location.

It can be set up from road to rail mode in under an hour, transit to the required site at up to 45km/hour on track, and be working within 15 minutes of arrival at site.

It carries up to three sets of heads and each set, dependant on the duty required, can machine 1500 to 2000 metres of rail. Heads can be changed in around 20 minutes and so up to 3500 metres of finished track can be achieved in one shift.

Between shifts the tips on the heads are either rotated or replaced in a purpose built workshop trailer that accompanies the road-rail vehicle, and within 12 hours the machine can be working again with the same, but refurbished, heads.

During this break period the machine can be refuelled and emptied of swarf and dust. With more sets of heads the process can become almost continuous and with a well-organised logistics team this is quite practical.

Inspection

The rail profile is built into the milling heads, so there is little chance of deviation from the desired dimensions. However, a number of tools can be used to check that the required standard, BS EN 13231-3 as a minimum, has been achieved.

For transverse rail profiles STRABAG Rail utilises either a DQM unit or a Mini-Prof for more exacting analysis, whilst a hand pushed trolley measures the longitudinal profile to check for corrugation. All such measurements are available immediately to check for compliance and quality control.

Following its successful trials on the DLR, the STRABAG Rail miller is coming back to the UK for further trials at 6 sites around the UK this November/December 2011.

Written by René Feuler for the rail engineer