On September 27, 2011, FEVE, the Spanish Government's narrow-gauge railway operating entity, demonstrated the first hydrolley (hydorgen hybrid fuel cell tram or streetcar) that is committed to go into public revenue service. This is planned for 2012. FEVE's railcar or "tranvía" is a Series 3400 unit, modified to for self-contained power, using 2 12-kW fuel cells plus lithium ion batteries and supercapacitors for regenerative braking and rapid re-acceleration.

My prediction: the Spanish innovation will have become the standard basic design for the vast majority of streetcars, and eventually light rail vehicles by 2020 and probably considerably sooner. In 2007, I co-authored an article in Passenger Transport predicting the ascendancy of this technology ( http://www.apta.com/passengertransport/Documents/archive_3701.htm ).