Rail travel is far more carbon efficient than previously thought, according to a rail industry group that has commissioned a new tool for calculating emissions.

The Rail Delivery Group (RDG), the association of train companies and National Rail that works to coordinate Britain’s railways, commissioned the development of the tool so that they could measure their carbon footprint properly.

The calculator, developed by Thrust Carbon, a sustainability intelligence platform, uses seven sets of data – including engine and fuel type, occupancy and carriage layout, and exact journey distance – to more accurately measure the footprint.

“The more granular you can get with the data, the better decisions can be made,” says Kit Brennan, founder and head of product at Thrust Carbon, who led the project.

Previously the calculation had been based on the UK government’s annual “greenhouse gas conversion factors for company reporting” data which involves one simple calculation – total energy consumed by the national rail network divided by total reported number of passenger kilometres travelled.

On the electrified rail route from London King’s Cross to Edinburgh Waverley station, figures showed emissions per passenger were 24kg/CO2e, where CO2e is a measurement used to show the total greenhouse gases emitted as an equivalent of carbon dioxide.

The first result from RDG’s new carbon calculator confirms this figure is actually 12.5kg/CO2e – approximately half the previous estimation, and 10 times less carbon than car travel or 13 times less than the equivalent flight.

The new calculations are part of the rail industry’s green travel pledge that aims to make travel sustainability information clearer so that travellers can make informed choices between transport options such as plane and car. This calculator will also enable businesses to measure their carbon emissions from rail travel more effectively.

“We want to empower businesses to make greener travel choices,” said Jacqueline Starr, RDG’s chief executive, who plans to make detailed carbon calculations for rail routes across Britain available by the end of the year.

Fuel use is a major factor, but there are also operational efficiencies to consider, Brennan said: “So, if a train runs but is completely empty, and you’re breaking down your emissions on a specific train then perhaps ticket prices should be lower to encourage more people to take those trains.”

He hopes that greater transparency with carbon emissions may add an element of healthy competition between rail operators that use the same train line: “That’s good because it encourages rail operators to invest in their trains, to have newer, more energy-efficient trains, and to lobby government to electrify more of the lines for the same reasons.”

Latest statistics from the Office of Rail and Road show that in 2021-2022, just 2km of track were electrified in Great Britain. “Basically HM Treasury has pulled the plug on electrification,” said Richard Hebditch, UK director at Transport & Environment, an organisation that campaigns for cleaner transport across Europe. “This new research from Thrust Carbon shows how electrified routes are clearly miles better for carbon savings, so it should be common sense for the government to have a rolling programme to electrify the rail network.”

“It’s basically stupid to have so many diesel-only routes, and older, polluting trains travelling around the system,” said Hebditch, who described the contrast between the old and new data as “dramatic”. He explains that the new calculator will not only show the variation of CO2 emissions between different rail routes but it will be possible to get a more accurate comparison between aviation and rail as well.

“This should be a catalyst for better understanding what’s on the railway and for showing that train travel is really good for minimal CO2,” said Hebditch. “This shows the clear case of the environmental advantages of supporting it. Hopefully, more [trains] will start to be electrified, routes can be decarbonised and we might see newer trains with regenerative breaking that put energy back into the system.”

Clive Wratten, chief executive at the Business Travel Association, said: “We’ve heard loud and clear from our members and the business travel community that consistency in carbon measurement is an imperative. This initiative from RDG on behalf of the whole rail industry has the potential to provide clarity and a robust green message to all parts of business travel.”

Once rail carbon information is displayed at point of sale, booking sustainable travel will be easier, especially when comparisons between rail journeys and flights are listed, Brennan said. “All our tools are about making sustainability effortless,” he added.

Plane or train?

A trip from Edinburgh to London on, say Monday 3 July, by train would start at £59, according to Trainline. It would take upwards of four hours and 40 minutes, and according to Thrust Carbon, would emit about 12.5kg of CO2 per passenger

A plane ticket from Edinburgh to London Gatwick on the same day would start at £65 (easyJet via Opodo) and take 1.15 hours (although that doesn’t include waiting times after check-in). And it would emit about 131kg of CO2.