Most engines or motors deliver power as torque through rotary motion: this is extracted from the linear motion of pistons in a reciprocating engine; water driving a water wheel; or forced gas or water in a turbine. From the point of delivery, the components of power transmission form the drive train.
Early automobiles often used chain drive or belt drive mechanisms rather than a driveshaft. Some even used electrical generators and motors to transmit power to the wheels
The automotive industry also uses driveshafts at testing plants where at an engine test stand a drive shaft is used to transfer a certain speed / torque from the combustion engine to a dynamometer
