The paper describes the progress made since 1945 in the electrification of the Southern Region of British Railways on the 750 V d.c. conductor-rail system. It gives details of fixed equipment, rolling stock and locomotives, and also touches on the important ancillary role of Diesel-electric propulsion in achieving the complete elimination of steam traction from an electrified area. There are particulars of loads on the national supply system created by extensions of electrification, and some mention is made of dual-powered locomotives, maintenance matters and future electrification policy on the Region.