Ultra-modern trains capable of running on both rail and road could be piloted in West Yorkshire.

Network Rail has revealed it is in talks with train company Northern Rail and the Department for Transport about the possibility of testing the technology in areas including Bradford.

This week, West Yorkshire transport chiefs are visiting Karlsruhe to see how the German city's tram-trains could be used to help fight congestion.

Councillor Ryk Downes, chairman of Metro, the West Yorkshire Passenger Transport Authority, said: "Savings made by using much lighter tram-trains on the York-Harrogate rail line into Leeds could be used to develop new on-street routes into Leeds city centre, to employment growth areas such as the Aire Valley and Five Towns and also to Leeds-Bradford airport."

Metro deputy chairman, Bradford Councillor Stanley King, said tram-trains would be his "favoured" solution along the traffic-choked Aire Valley and in busy town centres.

He said they could also be the best hope of providing a new transport link to Leeds-Bradford airport after plans for a rail link to the Yeadon-based airport floundered.

Metro officials have already visited Germany to see the technology at close quarters and, last year, transport chiefs in West Yorkshire said they wanted to bring tram-trains to the region as part of a £4.5bn proposal.

Coun King said: "I know tram-trains are a way forward because there are plenty of them on the continent.

"They are very successful because they can penetrate beyond railway stations. I favour it as a long-term project.

"It would bring a lot of benefits to West Yorkshire by getting cars off the roads and getting people to their destinations a lot more quickly."

If the Leeds City Region was chosen for the pilot project, services in Bradford, Harrogate and Wakefield could become the preserve of tram-trains, which are designed for smaller and medium-sized journeys.

The tram-trains, which do not cost as much as conventional trains to set up, would run on electricity on rail lines but diesel on roads, avoiding the need to electrify miles of new track.

Parts of Bradford's hilly landscape would present a challenge to the technology, according to Coun King, who said: "We would have to watch the geography a bit because they are not very good on steep hills, so you would struggle getting one up to Queensbury."

Bradford's inclines have already proved too much for the 30-seat battery-operated mini-tram' when it was given a six-week trial in October A Network Rail spokesman said background talks were taking place, which were in an early stage, to look at piloting tram-train technology.