If you spotted this train trundling through north Gloucestershire, you might not have taken much notice.

But its livery indicates that this is no ordinary service: powered by on-board batteries, the Class 320 loco is the UK's pilot for a system of train travel that could revolutionise live on the the rails and turn it a deeper shade of green.

Great Western Railway's innovative FastCharge battery trial achieved another significant step, says the operator, when it set a new UK record of 86 miles (138km) on battery power alone, with no need to recharge.

In a trial held last week that included journeys between Moreton-in-Marsh and Honeybourne North Junction, the train completed a 70-mile move from Long Marston to Reading Train Care Depot - and used just 45 per cent of its battery capacity.

GWR's team of specialist engineers on board the train claim it could have travelled more than 120 miles on a single charge.

Dr Simon Green, GWR Engineering Director, said the train, now at Reading, is set to undergo compatibility testing and preparedness for future maintenance and servicing requirements.

Dr Green added: "We were delighted by how the battery train performed during its series of test runs. In fact, it's fair to say it has surpassed the expectations of our team of engineers.

"Achieving these distances gives us great confidence as we press forward with this industry-leading FastCharge technology.

He stressed that the results were very much in a "real-world environment"with 86 miles covered at speeds of up to 60mph. The journey also included stopping and starting over a hilly route, with elevation changes of up to 200m.

GWR says that its FastCharge technology is designed to solve the problem of delivering reliable, battery-only trains capable of fulfilling timetable services on branch lines, eliminating the use of diesel traction and helping to meet government and wider rail industry's targets for net-zero carbon emissions by 2050.

A spokesman added: "The use of batteries for extended operation has typically been constrained by their range and meant widespread implementation has, until now, not been possible. It also negates the need for overhead electric lines which are expensive, time consuming to install and impact the landscape."

The train's tech is seen as a pathway to a reduction of GWR's emissions alone by more than 1,700 tons of carbon per year.

He added: "It is hoped the technology could one day see battery-powered trains in operation across the UK's approximately 2,000 miles of 80-plus branch lines.

In the buts and bolts of GWR's business plan, in February 2022, a deal was signed with Vivarail to trial new battery-charging technology designed to support the wider introduction of battery-powered trains on the UK's rail network.

Vivarail entered administration in December 2022, but GWR agreed contracts to buy intellectual property, rolling stock and equipment relating to the FastCharge technology.

Charging rails and line-side battery banks have been installed at West Ealing in preparation for the start of the trial on the Greenford branch line, and initial plans are for the train to run in non-passenger service alongside scheduled passenger services.