British Rail Class 707

British Rail Class 707 Desiro City
A pair of Class 707s at Clapham Junction
In service	Due to enter service in 2017–2018
Manufacturer	Siemens
Built at	Krefeld, Germany
Family name	Desiro
Constructed	2016–17
Number under construction	30 units to be built
Formation	5 carriages per set
Fleet numbers	707001–707030
Capacity	275 seats, 533 standing
Operator(s)	South West Trains
Depot(s)	Wimbledon Traincare depot
Line(s) served	Various
Specifications
Width	2.80 m (9 ft 2 1⁄4 in)
Floor height	1.10 m (43.31 in)
Maximum speed	160 km/h (100 mph)
Electric system(s)	750 V DC Third rail
Current collection method	Contact shoe
Track gauge	1,435 mm (4 ft 8 1⁄2 in) standard gauge
Notes
Sources : Desiro City data sheet Except where noted

The Class 707 is an electric multiple unit being built by Siemens as passenger trains for South West Trains. A total of 150 vehicles will be built, formed into 30 five-car units, and are being built to provide initially for 18,000 additional peak-time passengers into London Waterloo, with a further 6,000 additional passengers capable of being accommodated on completion of associated infrastructure improvements.

In September 2014 South West Trains announced plans to procure a total of 30 five-car trains as a means of expanding the fleet used to operate services out of London Waterloo. As a result of significant infrastructure improvements to allow the operation of 10-car trains across large parts of the SWT network, the operator procured significant amounts of additional rolling stock to allow for this. SWT's fleet is largely made up of Desiro units built by Siemens, and the Class 707 will be a follow on of this, as the second product purchased for use on the British network from the Desiro City range (following the purchase of the Class 700 for Thameslink). SWT will pay Siemens £210 million for the trains.

Construction of the first vehicles began in October 2015, with the first unit completed in March 2016. Testing is due to be undertaken at Siemens' Wildenrath facility from May 2016, entry into passenger service planned for June 2017, with all 30 planned units to be delivered by the end of 2017.

The first two Class 707 units are being delivered initially as dual-voltage units with pantographs for operation on 25 kV 50 Hz AC catenary. This is a temporary arrangement for testing purposes, with this equipment planned to be removed before the units begin revenue service. The rest of the fleet will be delivered with just 750 V DC shoegear for use on third rail electrified lines, but all units will have the ability to be modified for dual-voltage use if required in future.