 By now the pre @-@ war electrification scheme had been revived . In 1957 electrification between Rickmansworth and Amersham and Chesham began . Chalfont & Latimer 's platforms were extended and a second platform was opened at Chesham on 3 July 1960 to prevent through operations to and from Baker Street from interfering with the Chesham – Chalfont & Latimer shuttle . An electric service using London Underground T Stock began operations between Chesham and Chalfont & Latimer on 16 August 1960 , with former MR electric locomotives hauling the through trains to and from London . A steam locomotive was kept on standby in the new second platform at Chesham , in case of a failure of the electric trains . From June 1962 both the T Stock and the locomotive @-@ hauled trains were replaced by the newly introduced London Underground A Stock . 
