The heavy mechanical assembly beneath a railcar that houses the wheels, axles, bearings, and suspension components. A standard freight car has two trucks, which pivot on a center pin to allow the rigid car body to negotiate curves. They bear the entire weight of the car and transmit braking forces to the wheels.
The car knocker found a cracked side frame on the lead truck of that tank car.
If you hear a North American railroader say truck, they mean the wheel assembly under the car, not a highway vehicle.
Also heard as
- bogie
Do not mix it up with
- Bogie: Truck is the standard North American term for the wheel assembly, while bogie is used in the UK and internationally.
Related terms
Bogie
A wheeled chassis or framework attached under a rail vehicle to provide support, suspension, and guidance along the track.
Hot box
An overheated wheel bearing on a railcar, a defect that can burn the end off an axle if missed.
Flange
The projecting inner edge of a rail wheel that keeps the vehicle on the track.