Water columns (Fig. 27.5) are provided to supply water to the locomotives. A water column consists of a vertical pipe with a surveilling arm of either a horizontal shape or the shape of a swan's neck. A bay hose spout is provided at the end of the arm to enable water to be diverted to the opening in the engine tender. A foot valve is fixed inside the water column and water is made available from a suitably located high service tank.
Water columns are provided in locomotive yards as well as at various stations, where engines are required to be watered and fuelled.