Moving goods by rail will be more cost effective and environmentally friendly due to longer freight trains being allowed.

The Rail Safety and Standards Board (RSSB) said its research into couplers – which connect wagons – found they can safely transport either 16% or 13% more weight, depending on their type.

It means around 12,000 freight wagons – more than half the total on Britain’s railways – can now form part of longer trains.

For a 50-mile return journey with 24 wagons, the number of wagons that can be pulled will increase to 27 and carbon dioxide emissions will be cut by 0.25 tonnes, according to the RSSB.

There will also be annual financial saving of £291,000 based on a train making 16 return journeys a week.

RSSB lead research analyst Aaron Barrett said: “It’s good to see the results of our research directly helping freight train operators.

“By enabling longer trains, more goods and materials can be hauled per journey.

“This will have a hugely positive impact on emissions and financial efficiency.

Rail minister Huw Merriman said the results of the Department for Transport-funded research are “hugely promising”.

He said: “It’s great to see how we’re continuing to improve our freight network so even more goods and materials can be moved with every journey, strengthening the UK supply chain.

“Government investment into new ideas and innovations is vital as we continue to strengthen the UK supply chain and strive towards greener freight and net zero by 2050.”

Maggie Simpson, director general of industry body the Rail Freight Group, said: “Rail Freight Group members have been working hard to improve the efficiency and performance of their rail freight services and look forward to moving more goods and materials on the new capacity this research has identified.

“RSSB’s research projects are bringing modern thinking and analysis to age-old issues and will enable more goods to be hauled by train without needing investment in new infrastructure or rolling stock.”