The mock up was developed during the design process for the train and includes examples of all the interior finishes planned.

Siemens has spent £80 million designing and developing the new Desiro City emu, which although derived from the earlier Desiro UK range, is around 25% lighter, has better performance and uses entirely new bogies which have already undergone dynamic testing in Germany.

The fleet of 115 new dual-voltage (750V dc/25 kV ac) 160km/h class 700 emus will be supplied as 55 12-car sets, each seating up to 666 passengers, and 60 eight-car trains, which will seat 427.

Thameslink2

Production is already well underway at Siemens Krefeld facility in Germany, with more than 45 body shells completed and painted. Fifteen vehicles have been fully assembled and will shortly be formed into the first trains for static testing. Two completed vehicles are currently at the Rail Tec Arsenal climatic testing facility in Vienna.

The trains are being bought by CLT, a leasing company set up specifically for the procurement of this fleet. The company is a special purpose vehicle comprising Siemens Project Ventures, 3i Infrastructure, and Innisfree PFI Secondary Fund.

CLT will lease the trains, initially to FirstGroup and subsequently to future operators of the Thameslink franchise.

The lease agreement calls for very high availability from the new fleet with 110 daily diagrams for the trains in 2019 (from a fleet of 115) with 107 in scheduled service and three eight-car reserve trains to cover for failures or disruption.

Two new depots are being built to maintain the fleet, one in north London at Hornsey and the other larger depot at Three Bridges between London and Brighton.

The first train is due to arrive in Britain in August 2015 and it will be based at Three Bridges for final testing on the Brighton - Bedford route. The first trains will be formally handed over to FCC on December 18 2015 for staff training, before entering passenger service in spring 2016. This will release class 319 and 377 emus for transfer to other operators.

The class 700s will feature 2+2 seating in both standard and first Class. Real-time passenger information systems will communicate information on the route and journey as well as real time information on connecting train services.

As the trains will only have cabs at the outer ends and full-width gangways there is substantially more space available for passengers than on the existing trains, which are formed of four-coach emus. The maximum passenger loading, including standing passengers, is 1754 for a twelve car-train and 1146 for an eight-car set.

Thameslink3

Disabled access will be facilitated by equipping stations with raised sections, which will be situated in an identical position at all stations so passengers know exactly where to wait.

The trains will be fitted with automatic train operation for use on the central core section of the route from Blackfriars to St Pancras where trains will run every two to three minutes with station stops of only 30 seconds.

The £6.5bn Thameslink programme is scheduled for completion in December 2018 with the rebuilt London Bridge station and new infrastructure links in north and south London enabling through journeys from Bedfordshire, Hertfordshire and Cambridgeshire to destinations in Kent, Sussex and Surrey.

With up to 24 trains per hour through central London there will be 80% more peak hour seats on the core cross-London section from 2018.