The new locomotives are designed for easier maintenance, will improve energy efficiency by using a regenerative braking system that will feed energy back into the power grid and will enhance mobility for the people, businesses and economy of the entire Northeast region.

ENGADGET: blogger-avatar

The hybrid recaptures energy through a process known as regenerative braking -- where the energy normally lost through braking or coasting goes to power the electric motor.

CNN: All About: hybrid transportation