Far from being seen but not heard, many would say that railway engineers shouldn’t even be seen. The maintenance and upgrading of the network, which proceeds twenty-four hours a day and 365 days a year (yes, really!), should all happen in the background and not affect passengers.

That’s probably not a bad philosophy, although it’s not always possible.

There will be times when a piece of work is too large to carry out in the early hours of the morning, even in stages, so the infrastructure has to be shut.

Sometimes this causes localised inconvenience – a few rail-replacement buses over a weekend and a small number of disgruntled passengers.

Major disruption

On other occasions, the disruption is more extensive, and hence more noticeable. An 18-mile length of the West Coast main line was closed in July 2013. Nottingham station was shut completely for 12 days and in a westbound direction (towards London) for five weeks. Major works can only be carried out when the railway is closed, both for safety and often because the tracks have to be removed and replaced, perhaps in a completely different configuration, and there is no getting around it.

The shame is that, when the railway reopens, very often passengers don’t see any difference. They then start to question whether the inconvenience (to them) was really necessary. They don’t notice the improved line speed, the two minutes saved off their journey, the fact that their train gets delayed less often. All they see, if they are observant, are a few bags of ballast lying alongside the railway, some odd-looking items of plant – seemingly abandoned – that disappear after a few days, and a number of pieces of ‘track’ (actually rail) that get rustier over time before they, too, suddenly vanish.

Then there is Thameslink.

The disruption is certainly there, on a grand scale. Ask anyone who uses London Bridge regularly. And the whole mess seems to be going on for EVER.

But once the dust settles, there is certainly something to see. A good example is Blackfriars station. Passengers with a bit of time on their hands can lean on the handrail, halfway across the Thames, and just take in the sights of London and its river. Simply stunning!


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Or go shopping in Borough Market, just outside the much-maligned London Bridge station, and look up at the huge-yet-elegant construction that is the Borough Viaduct, shortly to be brought into use as part of the next tranche of work at the station next door.

The project is certainly leaving a legacy of something to see, and these were only two examples.

Latest landmark

The latest structure to be added to this list is a little more discrete but is still quite visible. Just south of Three Bridges station, on the Brighton line near Crawley, Siemens and Govia Thameslink Railway (GTR) have built a new train depot with large buildings on both sides of the railway. Constructed by VolkerFitzpatrick to plans originally submitted by Arup, it’s hard to miss, really.

On the western side of the tracks is the Main Facilities Building (MFB), a huge ‘shed’ that is 256 metres long and 40 metres wide. It has five roads, each capable of taking a complete 12-car Thameslink train. One is for heavy maintenance, with two bogie drops supplied by Sheffield- based specialist Mechan.

All of the roads have the rails supported on posts so that there is effectively a large ‘pit’ for technicians working under and alongside the train. Each has a 2.5 tonne overhead crane above it, to make light work of removing HVAC (heating, ventilation, air-conditioning), pantographs and other roof-mounted equipment.

Although on the third-rail 750V DC network, one road has a length of 25kV AC contact wire above it. This is so that the new Siemens Class 700 trains, which have to operate on both the 25kV AC network north of the Thames and DC third-rail south of it, can be tested after maintenance. It is not intended to actually be used for test running, though to move a few metres should be possible, but it will allow pantographs, transformers and busbar systems to be checked before trains are returned to service.

Naturally, interlocks are in place to make sure that nobody has access to the trains at high-level while the overhead power is on. These, along with the rest of the depot protection system, have been provided by Zonegreen.

There are no DC third-rails in the workshop (sorry, MFB) – trains are pushed in and out using the depot’s own battery-operated shunter.

The trains are coming

At the moment, the whole place is very new, clean – almost shiny, and quiet. The loudest noise is the sound of the ventilation fans. Two new trains, also very shiny, sit unmoving on two of the roads. Soon, however, when mainline testing starts next month, things will be a bit more hectic. Seven complete trains, one of them a shorter, eight-car unit, are awaiting shipment to the UK from Siemens’ test track in Wildenrath, Germany. Five trains will be at Three Bridges by Christmas.


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A second eight-car Class 700/0 train (the 12-car versions are designated 700/1) is currently undergoing braking trials at Velim in the Czech Republic. Although part of the same family, the 700/0 is viewed as a different train from a 700/1 so it needs to go through its own, independent test programme.

In total, there will be 60 eight-car and 55 12-car trains, all to be built by Siemens at Krefeld in Germany and tested at Wegberg-Wildenrath before delivery. The trains are being bought by Cross London Trains, a consortium of Siemens, Innisfree and 3i Infrastructure, using finance from 19 banks. Eversholt Rail is providing long-term asset management of the fleet.

All those trains will need a lot of space, and the new facility at Three Bridges will play a key role.

As well as the main MFB, there is a new tandem-head wheel lathe from Hegenscheidt outside in a separate building. Also in their own sheds are two carriage wash machines, one on the western side of the main line with the buildings already mentioned, the other on the eastern side to support those trains stabled over there.

A long building lies alongside the eastern carriage wash. This is the single-road under frame cleaning station, used to thoroughly clean the underside of trains before heavy maintenance and also to remove the unfortunate results from any collision between the train and animals or suicides.

Along with stabling on both sides of the main line, there are also additional sidings alongside the branch to Horsham. This is also the site of Network Rail’s Three Bridges Railway Operating Centre (ROC). Designed and built by Spencer Rail, this opened in January 2014 and will take over, by stages, control of the Brighton main line from London Victoria and London Bridge to Brighton, as well as the south coast and large areas either side.

High-tech equipment

The systems built into the new Three Bridges depot are impressive. Automatic inspection systems using lasers measure and predict when components such as brake pads need to be maintained and renewed. More lasers are used to examine wheel profiles and to decide whether a particular train needs to visit the wheel lathe.

Driver training can be carried out on-site using a simulator. This will provide the specialist training each driver must undergo in order to drive a new Class 700 train, from theoretical practice to practical reality.

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With a site that is over 1.4 miles long, on two sides of the main line, and with all of the switches and crossings for the workshops and multitude of storage sidings, the whole depot has to be fully signalled.

Everything has come together into one integrated system. And that’s key. As Iain Smith, programme director of the Thameslink rolling stock project at Siemens, said: “Three Bridges depot is of particular importance to the overall Thameslink Programme due to its role in commissioning the state-of-the-art trains. Without a working depot, we can’t fully test trains, perform maintenance or put them into service.”

Further facilities

Three Bridges is just one of the new facilities that will support the Thameslink fleet. A second smaller depot at Hornsey will open in 2016. This will be a 25kV AC depot and was originally going to be even larger than Three Bridges. However, local opposition meant that plans were recast and that Three Bridges was enlarged from three roads to five while Hornsey was reduced in size from a proposed six-road shed to only three.

In addition, improvements have been or are being made to outlying stabling facilities at Brighton, Horsham, Tonbridge, Selhurst, Cricklewood and Bedford.

So there’s plenty to see and, once the first new Class 700/1 train enters service early next year, even to ride on!