Built in 1928 by Swiss Locomotive Works. Electrical equipments supplied by Metropolitan Vickers, UK. This DC electric locomotive was amongst the first lot of 41 electric locomotives to come to this country. It was specially designed for goods operations and had a high tractive effort. Sister engines to the EA/1s, the EF/1s were used for heavy freight and banking operations on the steep hilly Bombay-Pune line. The EF/1s had an articulated frame, suitable for rounding the sharp bends on the ardous hill route. The engines are styled around the renowned Swiss 'crocodile' class of engines, so called due to their low slung profile and very long wheelbase, and an alleged resemblance to that animal while rounding bends. It is indeed a tribute to Swiss technology that the crocodile EF/1s were still at work till as recently as 1992, shunting at Bombay VT and Lonavla. Despite re-numbering after being re-classed WCG/1, they still have the old EF/1 number. These locos eventually retired in 1974. The pantograph was manipulated by a pole inside the pilot's cab. Several of the EF/1s had steam-locomotive type of whistles, later replaced by an electric horn. The EF/1s were among the first batch of electrics delivered to the IR in 1930. This loco was christened 'Sir Leslie Wilson' after the then Governor of Bombay.