The New Zealand Railways Magazine, Volume 4, Issue 7 (November 1, 1929)
Electrification is now recognised as the most satisfactory method of meeting operating problems associated with the working of passenger traffic over busy city and suburban railway routes. Intensive steam-operated services, such as are, for example, employed at the Liverpool Street terminal in London of the London and North Eastern Railway, meet modern requirements up to a point, but in every growing city it is only a matter of time before electric working becomes standard practice. London, Paris, Manchester, Newcastle-on-Tyne, and other European centres have their extensive systems of electric lines, the Southern Railway of England actually operating in the London area, the largest individual electric suburban railway system in the world.
Ever since the introduction of grouping in 1921, the Southern Railway has been working steadily towards the complete electrification of its tracks in and around London. Already some 750 track miles have been converted from steam to electric traction, and, by about next June, extensions recently put in hand will give this Company an electrified trackage of 800 miles. The new routes to be electrified are those between Hounslow and Windsor; Dartford and Gravesend, and Wimbledon and West Croydon. Direct current at 1,500 volts, with third rail transmission, is the system employed, trains composed of motor and trailer cars being worked on the familiar multiple unit arrangement. The new developments will provide for a service of trains in each direction every twenty minutes. Last year the Southern Railway handled 6,500,000 more passengers than in 1927, and in 1927 there was an increase of 11,500,000 passengers over 1926. In securing this increased passenger business, electrification has played an important part. At this stage in electrification's development it is unnecessary to dwell upon the rare appreciation of electric working, displayed by almost every traveller. In electrifying their Otira and Lyttelton-Christchurch tunnel sections, the New Zealand Government Railways have done much to earn the goodwill of the public.