The paper gives a general account of the suburban and main-line electrification scheme on the Great Indian Peninsula Railway. The first portion sets out the circumstances under which the scheme was initiated, the principal reasons for the decision to electrify the surburban and the main-line services, the actual and anticipated traffic, and the general programme of carrying out the work.The second portion deals with the local conditions which determined the design of a good deal of the plant and apparatus. This is followed by brief references to special points in the installation and design of the multiple-unit trains, electric locomotives, track equipment, bonding, substations, transmission system, power station, locomotive shops and car sheds, and system control. Such information as is available is given as to the capital cost of the complete scheme.The last two sections contain a number of statistics of operation and notes of operating experience, and the paper concludes with an Appendix in which are given for reference the names of contractors and principal sub-contractors, and the technical particulars of the plant supplied and installed.