Motive power depot

Motive power depot, usually abbreviated to MPD, or railway depot is a term given to places where usually locomotives are housed when not being used, and also repaired and maintained. They were originally known as "running sheds", "engine sheds", or, for short, just sheds. Facilities are provided for refuelling and replenishing water, lubricating oil and grease and, for steam engines, disposal of the ash. There are often workshops for day to day repairs and maintenance, although locomotive building and major overhauls are usually carried out in the locomotive works.

MPDs in Britain are now often known as traction maintenance depots.

German practice

The equivalent of such depots in German-speaking countries is the Bahnbetriebswerk or Bw which has similar functions, with major repairs and overhauls being carried out at Ausbesserungswerke. The number of these reduced drastically on the changeover from steam to diesel and electric traction and most modern Bw in Germany are specialised depots, often responsible for a single rail class.