The impact of technology on traction drives-a comparison of Jubilee and Northern Line trains

Over the years, many claims have been made for the advantages offered by new technologies in the field of railway traction motor drives. This paper looks at recent developments in technology and assesses objectively how much improvement these have delivered. It also shows how changing customer requirements, reflecting the increasingly business performance led nature of contracts, have been reflected in changes in the design and how developing technology has facilitated this process. This is done by comparing the traction drive systems of the trains built for London Underground Ltd´s Jubilee and Northern Lines. These are very similar, being supplied by the same main contractor and traction equipment supplier, for the same customer and to similar requirements. This comparison includes a quantitative assessment against an “ideal” traction drive