text: Multiple working is a term used on the UK rail network to describe the practice of having more than one diesel or electric locomotive hauling a train under the control of one driver .
simplified: The term can also apply when diesel or electric multiple unit trains are coupled together and also under the control of one driver . ` In tandem ' is the term usually used in the UK when more than one diesel or electric locomotive are hauling a single train and under the control of a driver on each locomotive .