A train can push OR pull. A front engine pulls, but engines can be added to the rear that push. When trains move backward, it pushes cars behind it (and rear engines assist by pulling).

If the train is at the front, it pulls. If it is at the back, it pushes. Typically trains pull there cargo

An autotrain is a push-pull train incorporating a steam locomotive and specially fitted passenger coaches.

It is a push and a pull. When you move your body towards the ground, it is a pull. A pull as in a pull to the ground. It is a push when you are moving away from the ground.

A push or a pull is a force