Why is there an diesel engine at the rear of a train?

Karen Wright on February 22, 2019

The most common reason is that it provides additional drive power to the train. Advanced answer is that certain trains have remote control locomotives at the rear (helpers) or in the middle (swing helpers) that can push the train up the hill and the use of dynamic brakes on down hills to slow the train. When you do this saves fuel and brakes shoes costs the less rail and keeps the air in the train brake line through the reduction of brake applications thus making the train safer.