what is rolling stock in railway

Rolling stock refers to all the vehicles that move on a railway, including both powered and unpowered vehicles such as locomotives, freight and passenger cars, coaches, wagons, and other vehicles used for support services. Rolling stock is considered a liquid asset since the value of the vehicle can be readily estimated and shipped to the buyer without much cost or delay. 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. Rolling stock components include car body, car body fittings, guidance (bogies and running gear), power system, propulsion, auxiliary systems, braking system, interiors, on-board vehicle control, passenger information system (PIS), communication systems, cabling and cabinets, door system, heating, ventilating and air conditioning (HVAC), tilt system, lighting, and coupler. The term "rolling stock" also includes transit vehicles such as buses, vans, cars, railcars, locomotives, trolley cars and buses, and ferry boats, as well as vehicles used for support services.