This article is about train cars. For the genre of motorsports, see stock car racing
Rolling stock comprises all the vehicles that move on a railway. It usually includes both powered and unpowered vehicles, for example locomotives, railroad cars, coaches, and wagons. However, in some countries (including the United Kingdom), the term is usually used to refer only to unpowered vehicles, specifically excluding locomotives which may be referred to as running stock, traction or motive power.
Rolling stock is considered to be a liquid asset, or close to it, since the value of the vehicle can be readily estimated and then shipped to the buyer without much cost or delay.
Additional definition with the above as the derivation: The road vehicles of a trucking company.
The term contrasts with fixed stock (infrastructure), which is a collective term for the track, signals, stations, other buildings, electric wires, etc., necessary to operate a railway.
Code names 
In Great Britain, types of rolling stock were given code names, often of animals. For example "Toad" was used as a code name for the Great Western Railway goods brake van, while British Railways wagons used for track maintenance were named after fish, such as "Dogfish" for a ballast hopper. These codes were telegraphese, somewhat analogous to the SMS language of today.
See also