ALSTOM Transport has developed a hybrid shunting locomotive for industrial applications in Europe. Built at the Stendal locomotive plant in Germany, the prototype 203 701 conversion of a former DB diesel-hydraulic is expected to receive formal certification next February and begin field testing in April 2007.

A 200 kW Deutz-engined diesel genset powers a DC link which charges a NiCd battery. The link is also connected to the traction inverter, which feeds two three-phase motors. The loco is designed to operate on genset or battery power alone, or with both sources offering a maximum of 550 kW. The power modules, electric motors and auxiliary converter are all standard Alstom designs proven extensively in other applications.

Because the prototype is a conversion of a diesel-hydraulic B-B, the motors drive through the existing mechanical transmission. To balance the weight of the centre-cab unit, the diesel engine and auxiliaries are mounted in one bonnet, with the batteries and traction inverters in the other. Alstom is also looking at converting diesel-electric locos to hybrid drive.

Starting tractive effort is 195 kN, falling to 20 kN at a maximum speed of 60 km/h. The performance curve compares closely to a conventional 500 kW diesel-hydraulic, with a maximum train weight of 3 000 tonnes.

Because most shunting locos are idling for around 75% of the time, Alstom estimates that the hybrid can cut fuel use by up to 40% and maintenance costs by 15%. As well as a 30% cut in life-cycle costs, the conversion offers a 15 dB(A) noise reduction and a 55% cut in emissions to well below the EU Stage IIIA requirements.