Power
Numerous forklifts are designed to operate on propane gas. Propane-powered forklifts are simple to refill. The gas is stored in a pressurized tank on the truck's back. The propane is pushed into the engine, where it is converted into vapor and afterward the vapor mixes with air. The forklift throttle is used to control the vapor flow. A spark plug fires up the mixture of vapor and air creating pressure which makes the pistons move. The pistons run the hydraulic pump and turn the wheels.

Because the types of forklifts that are operated by propane are clean burning and have low emissions, they are best to be used in warehouses and other buildings.

Hydraulics
What allows a forklift to raise and move heavy stuff from one location to another is the hydraulic system. A pump, tubes and cylinders make up the hydraulic system. The pump forces dense fluid in the tubing and into the cylinders. The build up of pressure pushes a piston, that lifts the forks. When the forks are lowered by the operator, the hydraulic fluid flows out of the cylinders and back in the pump.

Steering
Propane forklifts work well where maneuverability is required. Unlike an automobile, a forklift makes use of its back wheels to pivot, that allows the forklift to pivot fast on a tight radius.