The British Rail Class 350 Desiro is a class of electrical multiple unit built by Siemens AG in 2004–05, 2008–09 and 2013–14. Thirty of these units, designated Class 350/1, were built for use by Central Trains and Silverlink on regional express services and services on the southern section of the West Coast Main Line. A further 37 Class 350/2 were ordered by London Midland in late 2007. All 37 units were delivered and in service by July 2009. A further 20 units are currently on order, which will be split equally between London Midland and First Transpennine Express. The London Midland units will be designated under the Class 350/3 subfleet, and the First TransPennine Express units designated 350/4. The Siemens Desiro UK family also includes units of Classes 185, 360, 380, 444 and 450.