During the harvest season you will see many semi-trucks and trailers on the road hauling grain to nearby elevators or farms.
A semi-truck refers to the actual truck, which has an engine along with a cab. Sometimes it’s also called a semi-tractor. A semi-truck engine has 350 to 600 horsepower.
A semi-trailer is hauled by the semi-truck. It has wheels but no front axle and no engine, so it cannot move on its own. The average size of a trailer is 48 feet. When attached to the truck, together, they form a tractor-trailer unit also referred to as a big rig or an 18-wheeler, based on the number of wheels on the unit as a whole.
There are a couple of different types of semi-trailers used for hauling grain. Locally, you may see trailers with hopper bottoms or dump gates. The hopper bottom trailer, the most popular, allows grain to flow out underneath the bottom of the truck through a hopper gate. Most trailers have two hopper compartments. The dump trailer hydraulically lifts up and dumps the grain out through the back gate.
Hopper bottom – Underneath the trailer is the hopper bottom where grain is released from the semi-truck into a grain pit for storage. Most trailers have two hoppers and gates which open and close.
Semi-truck – Farmers and truckers haul grain with semi-trucks or sometimes called semi-tractors. This is the front of the truck with the cab. This semi-truck also has a sleeper berth for overnight trucking.
Semi-truck and trailer – The semi-trailer is pulled by the semi-truck. Together, they form a tractor-trailer unit also referred to as a big rig or 18-wheeler, based on the number of wheels. This grain trailer has two hoppers for unloading grain.