The British Rail Class 700 is an electric multiple unit passenger train from the Desiro City family built by Siemens Mobility. It is capable of operating on from overhead wires or 750 V DC from third rail. 115 trainsets were built between 2014 and 2018, for use on the Thameslink network, as part of the Thameslink Programme in the United Kingdom. , they are operated by Govia Thameslink Railway.
In 2011, the consortium Cross London Trains (XLT) consisting of Siemens Project Ventures, 3i Infrastructure, and Innisfree was announced as preferred bidder with Siemens Mobility to manufacture the trains. The decision was politically controversial as the trains were to be built in Germany, while the competing consortium led by Bombardier Transportation had a UK train factory. Both the procurement process and final close of contract were significantly delayed, resulting in the expected first delivery date moving from 2012 to 2016. The £1.6 billion contract to manufacture and provide service depots for the trains was finalised in June 2013. The first train was delivered in late July 2015.
A fleet of 60 eight-car and 55 twelve-car trains entered service between Spring 2016 and 2019. Having replaced s, , and , Class 700s are the only trains operated on the Thameslink network. Each train is able to reach 100 mph (160 km/h) and carry 1,146 passengers in an 8-car train, and 1,754 passengers in a 12-car train. Maintenance depots have been built at Hornsey and Three Bridges.
Procurement
Announcement
The Department for Transport began its procurement process (Thameslink Rolling Stock Project, or Thameslink Rolling stock Programme) on 9 April 2008, with the aim of introducing more passenger capacity on Thameslink lines to match expected demand. In addition, the bidders were to provide depots for vehicle maintenance and storage and finance for the rolling-stock project whereby revenues would be generated from the long-term leasing of rolling stock to the train operating company and associated maintenance payments.
The general specifications included: high reliability, short station dwell times, integrated information technology including passenger information and information for vehicle maintenance, a top speed of , and high acceleration and deceleration performance in line with a high-frequency timetable. The trains were to be designed for low weight, low track forces, and high energy efficiency. A standard 12-car train was to be about long and shorter 8-car trains were limited to .
The passenger accommodation was to include versions for both "metro" and "commuter" trains, based around a 2+2 seating arrangement, with fold-up seats and designed for high levels of standing passengers. Ride quality and noise levels were expected to equal or be better than those of current vehicles and climate control (air-conditioning) was to be fitted. The vehicles were to be fitted for driver-only operation, and to include GSM-R communications radio, as well as AWS, TPWS, and ERTMS level 2 safety systems. The ability to be used in 'Automatic train operation' (ATO) mode, where an on-board computer controls the motors and brakes, was also specified.
Vehicles were to operate on 750 V DC and 25 kV AC electrification systems, with regenerative brakes. Maintenance time was to be reduced by the use of modular components, remote diagnostics, and the avoidance of over-complicated systems. The Department for Transport gave a target of when empty for a train.
Bids
In July 2008, the Department for Transport shortlisted consortia including Alstom, Bombardier, Hitachi, and Siemens as train builders. The invitations to tender were issued to the four bidders in November 2008.
Hitachi exited the bidding process in April 2009.
In July 2009, Siemens unveiled the Desiro City, a development of design and technology used in its Desiro UK range and the Desiro Mainline range. Development of the design had begun in 2007, with an investment of about £45 million.
In September 2009, Alstom unveiled the X'trapolis UK, unusually an articulated vehicle, using 15.6 metre (51 ft) cars, with individual carriages proposed to be supported at one end by a bogie and at the opposite end by a linkage to the next carriage. The shorter vehicle allowed a slightly wider design; the smaller number of bogies was to have resulted in a train approximately 40 tonnes lighter than a conventional design. However, the design would have resulted in a higher axle load. The bid was rejected in October 2009.
Bombardier Transportation offered the Aventra, a design incorporating a development of the FLEXX Eco inside frame bogie with bogie-mounted traction motors.