Five new tram-trains, which can run on both railway tracks and tram lines, will replace conventional trains currently used on the 37-mile Penistone Line between Huddersfield, Barnsley and Sheffield (link below.)
http://www.gnn.gov.uk/environment/fullDetail.asp?ReleaseID=361330&NewsAreaID=2&NavigatedFromDepartment=False

The trial, which starts in 2010 and will take two years, will look at the environmental benefits, operating costs and technical suitability of the tram-trains as well as testing how popular the vehicles are with passengers on the route. There is also an option for a second phase which would test the vehicles on the Sheffield Supertram system to see what additional benefits the vehicles can deliver when extended onto city centre tram lines.

The project is a partnership between the Department for Transport, the train operator Northern Rail and rail infrastructure owner Network Rail and seeks to establish whether tram-trains similar to those operating successfully in Europe are suitable for Britain's railway network.

Northern Rail, which is owned by Serco-Ned Railways, will run a competition for manufacturers to build the tram-trains, which Northern will lease, and Network Rail will spend £15m in track improvements and alterations to stations as part of the trial.

DfT will contribute £9m to fund the operation of the trial and Northern will bring experience from Europe through Ned Railways who operate tram-trains in The Netherlands.

The Penistone Line has been chosen for the trial because it offers the chance to test the tram-trains on a route that in part is for passenger trains only and in part for passenger and freight trains.

Courtesy of Stop The Train (http://www.stopthetrain.org.uk/) here are a couple of video reports.
http://news.bbc.co.uk/player/nol/newsid_7300000/newsid_7303000/7303028.stm?bw=bb&mp=wm&news=1&nol_storyid=7303028&bbcws=1

http://news.bbc.co.uk/player/nol/newsid_7220000/newsid_7220100/7220186.stm?bw=bb&mp=wm&news=1&nol_storyid=7220186&bbcws=1

BBC article link.
http://news.bbc.co.uk/1/hi/england/bradford/7303727.stm