In 2008, Network Rail and the Department for Transport announced a trial of tram-train technology on the Penistone Line, a mainly rural route connecting Huddersfield and Sheffield via Barnsley.

Metro Chairman Councillor Ryk Downes said, "Metro has been at the forefront of calls to bring tram-trains to the UK and the fact that Network Rail is holding the UK trial in our own back-yard on the Penistone Line means we can monitor it closely and use its findings as part of the business case for tram-trains that we are putting forward as part of our 25-year Transport Vision," he said.

"We have been to Germany where tram-trains have been working very successfully and spoken to our overseas colleagues about their schemes, and we are convinced they are one of the answers to combating congestion in the Leeds City Region.

"Tram trains would be a way of increasing capacity on the busy Leeds, Harrogate, York line, and the reduced costs of running them would provide new opportunities to run lines in to town and city centres, extend routes into areas of growing employment and create a much-needed link to Leeds Bradford International Airport."

Find out more on tram-trains and tram-trains in Karlsruhe.