A hybrid train is a locomotive, railcar or train that uses an onboard rechargeable energy storage system (RESS), placed between the power source (often a diesel engine prime mover) and the traction transmission system connected to the wheels.
A hybrid train combines a traditional locomotive with an onboard battery system for propulsion. This system is situated between the power source, typically a diesel engine, and the wheels, which are powered by the energy stored in the battery.