The British Rail Class 230 D-Train is a diesel electric multiple unit or battery EMU built by rolling stock manufacturer Vivarail for the British rail network. The units are converted from old London Underground D78 Stock, originally manufactured in 1980 by Metro-Cammell. The conversion re-uses the D78's aluminium bodyshells with new interiors. It runs on the same bogies but these are rebuilt to as-new standard by Wabtec and fitted with brand new three-phase AC induction motors sourced from Austria. The initial build of three vehicles for London Northwestern Railway replaces the four-rail traction-current system with four diesel gen-sets, driving eight traction motors via purpose built electronic traction control units.