A headstock of a rail vehicle is a transverse structural member located at the extreme end of the vehicle's underframe. The headstock supports the

coupling A coupling is a device used to connect two shafts together at their ends for the purpose of transmitting power. The primary purpose of couplings is to join two pieces of rotating equipment while permitting some degree of misalignment or end mov ...

at that end of the vehicle, and may also support buffers, in which case it may also be known as a buffer beam. The headstocks form part of the

underframe An underframe is a framework of wood or metal carrying the main body structure of a railway vehicle, such as a locomotive, carriage or wagon. See also * Chassis * Headstock * Locomotive bed * Locomotive frame A locomotive frame is the struct ...

of a

locomotive A locomotive or engine is a rail transport vehicle that provides the motive power for a train. If a locomotive is capable of carrying a payload, it is usually rather referred to as a multiple unit, motor coach, railcar or power car; the ...

or a

railroad car A railroad car, railcar (American and Canadian English), railway wagon, railway carriage, railway truck, railwagon, railcarriage or railtruck (British English and UIC), also called a train car, train wagon, train carriage or train truck, is a ...

. The headstocks of

locomotives A locomotive or engine is a rail transport vehicle that provides the motive power for a train. If a locomotive is capable of carrying a payload, it is usually rather referred to as a multiple unit, motor coach, railcar or power car; the ...

railcar A railcar (not to be confused with a railway car) is a self-propelled railway vehicle designed to transport passengers. The term "railcar" is usually used in reference to a train consisting of a single coach (carriage, car), with a dri ...

s and cabcars also support

headlamps A headlamp is a lamp attached to the front of a vehicle to illuminate the road ahead. Headlamps are also often called headlights, but in the most precise usage, ''headlamp'' is the term for the device itself and ''headlight'' is the term for ...

and the hoses for air brakes, vacuum brakes as well as the

cables Cable may refer to: Mechanical * Nautical cable, an assembly of three or more ropes woven against the weave of the ropes, rendering it virtually waterproof * Wire rope, a type of rope that consists of several strands of metal wire laid into a hel ...

for train control and

head end power In rail transport, head-end power (HEP), also known as electric train supply (ETS), is the electrical power distribution system on a passenger train. The power source, usually a locomotive (or a generator car) at the front or 'head' of a train, p ...

Length over headstocks

A commonly used measurement relating to a rail vehicle is its length over headstocks, which is the length of the vehicle excluding its couplings or buffers (if any). Alternative expressions for length over headstocks are length over coupler pulling faces, usually applied to

Janney coupler Janney couplers are a semi-automatic form of railway coupling that allow rail cars and locomotives to be securely linked together without rail workers having to get between the vehicles. They are also known as American, AAR, APT, ARA, MCB, knuckl ...

s, and length over buffers.

References

Locomotive parts Rolling stock {{rail-transport-stub