BREL major production centres were at Crewe (Crewe Works), Derby (Derby Carriage and Wagon Works and Derby Works), Doncaster (Doncaster Works), Shildon (Shildon Works) and York (BREL York).
Not all British Rail rolling stock was built in house: Metro Cammell, Brush Traction and Metropolitan-Vickers amongst others manufactured rolling stock, although in general it was built to BREL specifications.