Energy / Climate Change

April 29, 2005


Hybrid Tram with On-board Batteries Successfully Tested

Keywords: Energy Conservation Environmental Technology Transportation / Mobility University / Research institute 

The Railway Technical Research Institute of Japan announced on February 2, 2005 that it had successfully completed a test run of its hybrid tram, which uses both on-board batteries and electricity from overhead lines.

Many electric trains currently use a regenerative braking system that converts the kinetic energy of the moving cars into electricity that is fed back into overhead wires. However, regenerative braking loses its effectiveness when there are no other trains running nearby that can immediately use the regenerated electricity. In such a case, the train must use friction brakes, which do not convert kinetic energy into electricity and are also subject to wear and deterioration of parts.

To cope with these disadvantages, the newly developed tram has a hybrid structure involving a combination of power supply from overhead lines and high-performance batteries. The same kind of battery was used in a battery-powered tram with no pantograph (device to collect power from overhead wires) that was developed and demonstrated by the Institute in August 2003. The hybrid structure of the new tram allows the electricity regenerated during braking to be stored in the batteries. The stored electricity is also used as energy for restarting the tram, which reduces the amount of power needed from overhead wires.

The Institute plans to conduct further trials using existing trams in and after fiscal 2005, as the success of this test has confirmed the feasibility of an electric train design that can substantially reduce losses of power from regenerative brakes, as well as of trams that can run with or without power from overhead lines.

Posted: 2005/04/29 06:16:21 PM
Japanese version