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A mechanism for transmitting rotation, which can be engaged and disengaged. Clutches are useful in devices that have two rotating shafts. In these devices, one shaft is typically driven by a motor or pulley, and the other shaft drives another device.

Roller Clutch

A mechanism for transmitting rotation, which can be engaged and disengaged. Clutches are useful in devices…

An automatic coupler.

Coupler

An automatic coupler.

A coupling is a device used to connect two shafts together at their ends for the purpose of transmitting power. Couplings do not normally allow disconnection of shafts during operation, though there do exist torque limiting couplings which can slip or disconnect when some torque limit is exceeded.

Electrical Coupling

A coupling is a device used to connect two shafts together at their ends for the purpose of transmitting…

In American practice all of the forces between the locomotive and cars are handled through the coupler and its associated draft gear, which allows some limited slack movement. Small dimples called "poling pockets" at the front and rear corners of the locomotive allowed cars to be pushed on an adjacent track using a pole braced between the locomotive and the cars.

Device for Controlling Draft in Locomotives

In American practice all of the forces between the locomotive and cars are handled through the coupler…