Push–pull is a configuration for locomotive-hauled trains, allowing them to be driven from either end of the train, whether having a locomotive at each end or not.
Push–pull train in Austria (2004); note locomotive at the rear of the train.
Push–pull train in the Czech Republic (2016); note control car at the rear of the train.
Push–pull train in the former German Democratic Republic
A modern driving van trailer in Ireland
A locomotive or engine is a rail transport vehicle that provides the motive power for a train. If a locomotive is capable of carrying a payload, it is usually rather referred to as a multiple unit, motor coach, railcar or power car; the use of these self-propelled vehicles is increasingly common for passenger trains, but rare for freight trains.
Pacific National diesel locomotives in Australia showing three body types, cab unit (front), hood unit (middle) and box cab (rear)
A Victorian Railways R class steam locomotive in Australia
A China Railways HXD1D electric locomotive in China
Wainwright SECR Class P on the Bluebell Railway, England