A research project undertaken by Britain’s Rail Safety and Standards Board (RSSB) has found that freight train lengths could be increased by revising the wagon coupler load ratings that determine maximum trailing weights and train lengths.

RSSB says that the change would allow freight operators to safely haul more wagons per train than current practices allow, reducing their environmental impact and improving financial efficiency.

The research project has gathered evidence that supports increasing a 34.5 tonne coupler rating by 16% to 40 tonnes. Some couplers currently rated at 56 tonnes could have this increased by 13% to 63 tonnes.

The enhanced ratings can be applied to wagons operating today without the need for modification work or a detailed engineering assessment. This would apply to over 12,000 wagons, more than 50% of the fleet operating in Britain.

The environmental and financial benefits have been confirmed by real-world case studies.

A train currently comprising 24 wagons operating for 80km each way would be able to be lengthened to 27 wagons, reducing CO2 emissions by 0.25 tonnes and producing projected annual cost savings of £291,000.

Increasing the length of a train operating for 376km each way from 14 to 16 wagons would save 1.4 tonnes of CO2, and reduce costs by £245,000 a year.

On a journey of the same length, increasing a 19-wagon train to 23 wagons would save £364,000 a year and cut CO2 emissions by 2.1 tonnes.

RSSB says that the improved freight coupler load ratings are now being implemented, with freight operators working to identify routes suitable for longer trains

“By enabling longer trains, more goods and materials can be hauled per journey,” says RSSB lead research analyst, Mr Aaron Barrett. “This will have a hugely positive impact on emissions and financial efficiency.”

“This research project is the first in a series, funded by the Department of Transport, designed to help the rail freight sector in Britain. Our freight research programme is currently focusing on the safe operation of rail freight, raising the average speed of services, enabling the operation of longer trains and reducing emissions.”

“This research is hugely promising,” says rail minister, Mr Huw Merriman. “Government investment in 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.”

Ms Maggie Simpson, director general of rail freight lobbying organisation the Rail Freight Group (RFG), says that RFG 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.”