truck

Two- or three-axled carriage whose wheels are guided by the track; it supports a locomotive or a car.

spring

Part absorbing vibrations caused by the wheels as they move along the track.

truck frame

Framework supporting the axles, suspension, brakes and traction motors.

journal box

Part connecting the axle to the truck frame.

axle

Transversal part under a vehicle passing through the hubs of the wheels, which support it.