Developed as a means of saving electricity - and thereby reducing operating costs - regeneration was banned after an accident between two tramcars in Rawtenstall in 1911. Trolleybuses developed the concept, not being included in the ban. Although it took the modern technology of the 1990s to perfect it, the story of the years between is quite fascinating. An unusual book representing a lifetime's work for the author and telling a hitherto little-known story - well illustrated with photographs, charts and diagrams an as up-to-date as October 2006.