Lithium iron magnesium phosphate battery technology produced by Valence, United States, is the first to meet the requirements of the project following testing at Valence's laboratory in Texas and earlier theoretical simulation work undertaken by Bombardier in Britain.

The batteries were tested in simulated conditions expected on the Greater Anglia network, including intensive branch line journeys which would require eight hours of continuous operation, as well as range, speed and temperature tests.

Bombardier, in cooperation with Greater Anglia, will now begin the process to fit the batteries to a class 379 train at its factory in Derby ahead of operation on a test track and under live conditions. The tests are set to be concluded by the end of next year.

"It's taken a lot of work to get this far," says Mr James Ambrose, NR's independently powered EMU (IPEMU) senior engineer. "As well as testing the batteries under simulated journey conditions, we've needed to get the donor train gauge cleared for the route the train has got to run on and gain a certificate of rolling stock/infrastructure compatibility."

Data gathered from the tests will be used to determine whether any future IPEMU will utilise batteries or hybrid power. NR says it hopes to deploy the vehicles on branch lines where it is not cost-effective to erect catenary and to bridge non-electrified sections of otherwise electrified railways.