Between 1926 and 1928 the Southern Railway electrified the SE&CR suburban lines at London Bridge using a third rail system, adapting the existing LB&SCR routes to it at the same time. The first electric services ran on 25 March 1928 from London Bridge to Crystal Palace via Sydenham, followed by a peak hour service to Coulsdon North on 17 June. This was followed by electric services to Epsom Downs via West Croydon, Crystal Palace via Tulse Hill, and Streatham Hill, and to Dorking North and Effingham Junction via Mitcham on 3 March 1929. At the same time as electrification, the SR installed colour light signalling. The Southern Railway electrified the Brighton Main Line services to Brighton and the South Coast, providing a full service to on 17 July 1932. This was following by a full electric service to Brighton and West Worthing on 1 January 1933, followed by services to Seaford, and on 7 July 1935 and to and on 3 July 1938.