A motive power depot (MPD) or locomotive depot, or traction maintenance depot (TMD), is where locomotives are usually housed, repaired and maintained when not being used. 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 locomotive works. (Note: In American English, the term depot is used to refer to passenger stations or goods (freight) facilities and not to vehicle maintenance facilities.)