Train manufacturers present theories on future power sources

Bi-mode, battery and fuel cell trains could all play a part in helping to reduce carbon emissions on the railway, say Hitachi and Bombardier.

The train builders supplied evidence to the Transport Select Committee’s Trains Fit for the Future inquiry in early September.

In Hitachi’s submission, it says that eliminating diesel passenger trains by 2040 provides an opportunity to boost economic growth, and that advances in battery technology could allow government to be even more ambitious with its decarbonisation targets.

It argues that bi-mode trains offer the opportunity to “break out of the energy source cold war” between the short-term expediency of diesel traction and longer-term aspirations for major electrification.

However, it acknowledges that battery and hybrid trains are not yet able to eliminate the requirement for diesel trains on long unelectrified routes. Battery capacity is expected to double by 2025, meaning the range of battery or hybrid trains would become more viable.

Hitachi says it is ready to add batteries to its bi-mode trains to work alongside diesel engines. Claimed benefits are better acceleration and a 10% or more reduction in fuel consumption.

By limiting emissions at stations, there could also be benefits in urban areas. It has already delivered a battery-only fleet in Japan, and suggests the technology is suited to the UK.

“Introducing battery technology does not have to work against the electrification of the UK railways. In fact, it can complement and help to reduce costs. Battery trains are able to act as a link between routes that are not electrified, unlocking new rolling stock for non-electrified routes,” it says.

Hitachi believes that fuel cell trains will only become a realistic option after 2040, due to the inefficiency in hydrogen storage and the method of production.

Bombardier takes a similar tack, highlighting its Aventra trains which can be produced as bi-modes with the diesel equipment swapped for other technology in the future.

It acknowledges the limitations of using fuel cells, but says that with potential ranges of up to 450 miles, such trains could make economic sense on long non-electrified regional lines.

Bombardier also believes that battery-powered trains recharging under overhead catenary or at charging stations offer a better solution than hydrogen trains, citing lower energy costs, quick implementation and energy efficiency over distances of up to 60 miles. The total cost of ownership of a hydrogen train is claimed to be up to 50% higher than a battery train over 30 years.

Thales also submitted evidence. It suggests algorithms could maximise the opportunities for trains to coast, and that moving block signalling (such as those used on some metro networks) could help to reduce energy consumption by up to 15%. Driver Advisory Systems are also said to cut energy consumption.

Thales also says extension of predictive maintenance could reduce the need for intervention, saving fuel consumption by engineering teams and halving the time needed for on-site inspections.