High Quality Content by WIKIPEDIA articles! The British Rail Class 350 Desiro is a class of electrical multiple unit built by Siemens AG in 2004–05, 2008–09 and 2012-14. 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 class 350/3, and the First Transpennine Express units designated class 350/4.