To run train (or run a train) refers to when multiple men have sex with a woman one after the other, with or without consent.

What is the front car of the train called?

The front of a train is called a "locomotive." The back of a train is called a "caboose."

How do trains run on tracks?

The wheels on each side of a train car are connected with a metal rod called an axle. This axle keeps the two train wheels moving together, both turning at the same speed when the train is moving. ... This is where the wheels' geometry comes in. To help the wheels stay on the track their shape is usually slightly conical.