Heritage Great Britain (HGB) has announced plans to invest £1.1m (US$1,4m, €1.3m) in hybrid diesel locomotives at its Snowdon Mountain Railway attraction in Snowdonia, Wales, in a bid to reduce its carbon footprint.

The new locomotives, developed by Clayton Equipment, are expected to come into service in May and will run alongside the traditional steam and diesel trains. They will be driven by maintenance-free electric motors and powered by a traction battery and a diesel generator. During the train's descent, the diesel generator will be turned off to prepare the engine for the ascending journey, whilst service braking recharges the battery.

Boasting a Euro 5 standard engine, the new locomotives will be more fuel-efficient and lower in emissions than the existing diesel fleet.

"We are extremely proud of the development of our new Hybrid Diesel Locomotives," said Mike Robertshaw, senior engineering manager at Snowdon Mountain Railway.

"This is a significant investment in new technology which will not only allow us to carry more passengers but also allow us to help the environment. This is just the beginning of further investment as we make it sustainable for the years ahead."

One of the most popular tourist destinations in Wales, Snowdon Mountain Railway welcomes more than 140,000 visitors per year and carries passengers to the summit of Mount Snowdon, where they can see spectacular views of Snowdonia National Park. Since it first opened in 1896, the railway has welcomed an estimated 12 million tourists from all around the world.