Rail transport is the movement of passengers and goods using wheeled vehicles called trains, made to run on railway tracks. In most countries, this transportation method helps trade and economic growth. Railways (British English) or railroads (American English) provide an energy-efficient way to transport material over land. The railway tracks are a large part of the system and provide smooth and hard surfaces on which the wheels of the train roll with a little friction. Also, the track spreads the weight of the train which means larger amounts can be carried than with trucks (all types: box truck, fire engine truck, concrete mixer truck, cutaway van chassis, tanker truck, dropside truck, logging truck, tow truck, garbage truck, stakebed truck, flatbed truck, sprinkler truck, semi-truck, and dump truck) on roads.