Chain drive is a type of transmission used in some Construction plant and in various road vehicles. The drive from the engine to the gearbox or from the gearbox to the wheels is by sprockets and chain. This may be in a 1:1 ratio or it may be a reduction set up to increase power at the wheels and reduce the speed.
Machines such as moxy dump trucks and Scammell Pioneers have the drive enclosed within a rocking beam arm to split it from a central axle to a pair of drive wheels on each side of the vehicle on double drive vehicles, rather than having 2 driven axles linked by a short propshaft. These transmissions use a heavy duty roller chain often of a duplex s design to cope with the loading.