A railway roundhouse is a building with a circular or semicircular shape used by railways for servicing and storing locomotives. Traditionally, though not always the case today, these buildings surrounded or were adjacent to a turntable.

A motive power depot (MPD) or locomotive depot, or traction maintenance depot (TMD), is where locomotives are usually housed, repaired and maintained. They were originally known as "running sheds", "engine sheds" or just "sheds". Facilities are provided for refuelling and the replenishing of water, lubricating oil and grease and, for steam engines, the disposal of ash. There are often workshops for day-to-day repairs and maintenance, but locomotive building and major overhauls are usually carried out at locomotive works.