Bletchley TMD

Bletchley TMD is a railway traction maintenance depot situated in Bletchley, Milton Keynes in Buckinghamshire, to the north east of Bletchley railway station, on a siding off the Marston Vale line. The depot is operated by London Northwestern Railway. The depot code is BY but, in steam days, the shed code was 1E.
The original London and North Western Railway locomotive shed in Bletchley was a wooden and galvanised iron building that catered for some twelve engines, with three roads accommodated within the facility. However during the 1870s the shed collapsed in a gale, burying stabled locomotives and was replaced by two gabled roof spans with numerous ducts and chimneys. When newly rebuilt, it would measure 250 feet in length, with a maximum width of 100 feet . These sheds were situated just north of the railway station on a siding to the west side of the West Coast Main Line, on a site now occupied by today's carpark.

Wikipedia