The British Rail Class 450 third-rail DC EMU began service during 2003. They are a part of the Siemens Desiro modular train family. Used for outer suburban services, the Class 450 was built with standard and first class accommodation. The unit has a maximum speed of 100 mph (161 km/h).
The Siemens “Desiro UK” family also includes units of Classes 185, 350, 360, 380 and 444. These trains are the most numerous trains in South West Trains’s fleet, and also the most numerous units in the Desiro UK family.
In August 2017, the units will transfer to South Western Railway, owned by FirstGroup and MTR Corporation.