A railway turntable or wheelhouse is a device for turning railway rolling stock, usually locomotives, so that they can be moved back in the direction from which they came. This is especially true in areas where economic considerations or a lack of sufficient space have served to weigh against the construction of a turn around.  In the case of steam locomotives railways needed a way to turn the locomotives around for return trips as their controls were often not configured for extended periods of running in reverse and in many locomotives the top speed was lower in reverse motion. In the case of diesel locomotives, though most can be operated in either direction,