The Thameslink programme is going well. A complex project to upgrade the existing route through the centre of London while also adding new London Bridge, which is currently destinations, disruption was always bound to occur but, by 2018, it will be complete and a staggering 24 trains per hour each way will be running on a twin-track railway through the centre of London.

The £6.5 billion project will see the original destinations of Bedford and Brighton augmented by Peterborough and Cambridge, from whence trains will run through the Canal Tunnels, joining the ‘traditional’ Thameslink route just north of the St Pancras platforms. At the southern end of the route, trains will terminate at Tattenham Corner, Horsham, Caterham, East Grinstead Sevenoaks and Maidstone in addition to Brighton.

All trains will call at St Pancras, Farringdon, City Thameslink and Blackfriars. The latter station has already been completely rebuilt to span the Thames.

Many services will also stop at London Bridge, which is currently getting a makeover. The work required is extensive and long-suffering  commuters are having to cope with an ever-changing situation. However, once complete, Thameslink’s services will have a dedicated path through the busy station for the first time ever.

All of this has been reported in Rail Engineer on many occasions, with Collin Carr, David Bickell and others keeping readers updated on developments.

But what of the trains? There was a big fuss when it was announced that Germany’s Siemens was to get the order rather than ‘British’ Bombardier, but what has happened since?

The order

A total of 1,140 carriages were ordered from Siemens. The contract was first announced on 16 June 2011 when Cross London Trains Ltd, a consortium formed by Siemens Project Ventures GmbH, Innisfree Ltd., and 3i Infrastructure Ltd, was revealed as the preferred bidder. It was the last day of Railtex that year, and the Siemens staff were understandably in celebratory mood.

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However, after delays in confirming the finance (a total of 19 banks were involved), the order was not signed until July 2013. By then, to hit production targets as the railway was still due to be complete in 2018, Siemens had already manufactured pre-series vehicles including bogies and traction equipment which were undergoing tests in Germany.

So once the go ahead was finally given, production could commence in earnest. Sixty 8-car and fifty-five 12-car units were specified, designated Classes 700/0 and 700/1 respectively.

The units all have a welded aluminium construction with inside-frame bogies. Four cars on the 8-car units, and six on the 12-car, will have both bogies powered while the others will be purely trailer vehicles. All trains will be dual- voltage, working off both 25kV AC and 750V DC supplies. Two pantographs will be fitted and both will be used in normal operation.

Mechanically, the trains will be symmetrical around the centreline. Both driving cars will be powered as will the third and sixth on the 8-car and the third, fourth, ninth and tenth cars of the 12-car.

One interesting way to quickly tell a power bogie from an unpowered one is to look at the brakes. Primary braking on the train is by regeneration, but the unpowered bogies have large vented disc bakes while the powered bogies, with no room for discs due to the traction motors inside the frames, have tread brakes.

Manufacturing process

The Class 700 trains are being assembled at Krefeld in Germany, close to Düsseldorf. Here the bodyshells are constructed from plank-like hollow aluminium extrusions. Several of these ‘planks’ are clamped together and welded up longitudinally on a large welding machine to form a solid side. More are clamped onto a curved jig and again welded to form the roof.

These large panels go into a huge, boxed-off milling machine where the window and door apertures are cut, together with any other holes for equipment and power access.

The floors are made in the same way except these are welded up by hand from sturdier elements, including two friction-stir-welded plates which will take the bogie attachments.

The four main elements are then welded together to make a recognisable bodyshell, and the fitting-out and painting can begin. Final assembly is done on a production line in five stages, number four purely being testing of the systems installed in the first three.

After assembly and test, the cars are made up into four- car units and hauled off to the test track for final assembly into finished trains and final testing.

3D planning

One interesting area of the Krefeld factory is a cinema- style room with a huge screen and no seats. Here, graphics of the trains can be displayed using information straight out of the design software. It doesn’t just give a view of the finished trains, it does it in layers and in three-dimensions.

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Wearing 3D glasses, viewers can therefore see each element of the train and how it interacts with others. By panning and rotating the view, it can be inspected from all sides.

There are many uses for this technique, but one of the most important is trial-assembly. The build sequence can be tested, and any conflicts, whereby a component cannot be installed as it will be blocked by something else, can be sorted out before assembly starts in the factory itself. This prevented all of the initial build errors that crop up in any complex assembly.

Under test

The first 12-car set arrived at the Siemens test and validation centre at Wildenrath (PCW – Prüf- und Validationscenter Wegberg-Wildenrath) in March 2014. This was only eight months after the contract was signed.

At the time of writing, six further trains, five more 12-car sets and the first 8-car, have also commenced testing. The programme includes performance testing, checks on ride comfort and safety systems, and racking up fault- free running. Driver training is also underway as Govia Thameslink Railway (GTR) trainers gain experience on the new trains so they can impart that knowledge to the rest of the drivers on their return to the UK.

The first train is due to arrive in the UK in August 2015 and, after testing under British conditions on the main line, be handed over to GTR in December. It should then enter passenger service sometime in February 2016, displacing a Class 319 set which will be cascaded elsewhere in the network.

From early 2016, trains will arrive at a rate of one a week until the entire contract is complete with the last unit handed over in June 2018.

Riding on the first prototype around the Wildenrath test track revealed a modern, quiet multiple- unit without any vices. The seats were quite hard, as is often found on commuter trains, with a 2+2 seating arrangement reflecting the fact that these are medium-distance trains and not just short-haul, standing- room-only commuter specials. Both conventional and accessible CET (controlled emission toilets) are included with the latter being in the centre of the train.

Doors are wide and there is a large open space adjacent to get people on and off. Luggage racks seem strong (a Siemens engineer was sitting in one) and well-placed.

The driving position is central – there is no gangway-connection between units on these trains – with a good view. As it was under test, the usual Driver’s Safety Device (née ‘dead man’s handle’) was disconnected and a load of test cables emerged from the desk, but it was simple for a novice to drive.

When in service, the trains will be fitted with large passenger- information displays which can also play video – ideal for both safety messages and advertising.

All in all, the trains look and feel good and testing is going well. The next step will be to see the first one in the UK in August – but where will it go?


115 trains, or 1,140 carriages, take up a bit of room – in fact just over 23 kilometres in total. Even with an old Class 319 being retired when a 700 goes into service, there will still be a considerable amount of space required, particularly as there will be a lag on the cascade.

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The two main depots for the fleet will be Hornsey on the East Coast main line, in 25kV country, and at Three Bridges on the 750V DC Brighton line.

Three Bridges is interesting in that it occupies both sides of the main line. The main five-road workshop is on the Up side with storage sidings between it and the main line. Facilities include a wheel lathe, carriage wash and two bogie drops. The southbound side has just sidings, a carriage wash and a full-length under-frame cleaning building. All sidings have CET emptying stations. The two parts of the depot are connected by a footbridge.

There is actually a third part to the site, behind the main maintenance facility on the line to Littlehaven, where some additional stabling, with CET emptying stations, has been constructed.

Hornsey is on a long, thin site that is already occupied by the depot for several classes of trains including Classs 319s. The original plan for a larger depot was rejected in 2009 and the resulting rethink reduced it in size and enlarged Three Bridges.

The reconstructed depot at Hornsey, which will be open for the new Class 700 trains in 2016, includes an updated wheel lathe, carriage wash, underframe cleaning building and a three-road maintenance shed.

Three Bridges will come on-stream before Hornsey and, when the first Class 700 arrives through the Channel Tunnel early in August this year, it will be taken to the West Sussex depot.

No doubt Rail Engineer will be there to see it.