Hybrid Train

A hybrid train is a rail vehicle or train that uses an on-board 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.

Surplus energy from the power source, or energy derived from regenerative braking, charges the storage system. During acceleration, stored energy is directed to the transmission system, boosting that available from the main power source. In existing designs, the storage system can be electric traction batteries, or a flywheel. The energy source is diesel, liquified petroleum gas, or hydrogen (for fuel cells) and transmission is direct mechanical, electric or hydrostatic.

Using a storage system means that a non-fully electric train can use dynamic braking, and even shut down the main power source whilst idling or stationary. Reducing energy consumption provides environmental benefits and economic savings.[1] A smaller scale version of the concept is found in hybrid automobiles, such as the Toyota Prius.