Power
Many forklifts are made to operate on propane gas. Propane-powered forklifts are easy to refill. The gas is stored inside a pressurized tank on the rear of the truck. The propane is pushed into the engine, where it is converted into vapor and the vapor combines with air. The throttle of the forklift is used to be able to control the vapor flow. A spark plug ignites the air and vapor mixture producing pressure that moves the pistons. The pistons turn the wheels and run the hydraulic pump.
Forklifts that use propane are recommended for use inside warehouses and other buildings because they are clean burning with low emissions.
Hydraulics
What allows a forklift to lift and move heavy stuff from one location to another is the hydraulic system. Cylinders, a pump and tubes make up the hydraulic system. The pump forces dense fluid through the tubing and into the cylinders. The pressure build up pushes a piston, that raises the forks. When the operator lowers the forks, the hydraulic fluid flows out of the cylinders and back into the pump.
Steering
Propane forklifts work well where maneuverability is required. Not like a car, a forklift makes use of its back wheels to pivot, which enables the forklift to turn quickly on a tight radius.