South African Class ES

South African Class ES
Class ES shunting locomotive, c. 1936
Type and origin ♠ Series 1 & 2 - ♥ Series 3 & 4 Power type Electric Designer South African Railways (A.G. Watson) Builder South African Railways Werkspoor Serial number Werkspoor 737-746, 913-924 & 1053-1054, SLM 3662 Model SAR ES Build date 1936-1964 Total produced 28
Specifications Configuration: ​  • AAR B-B  • UIC Bo'Bo'  • Commonwealth Bo+Bo Gauge 3 ft 6 in (1,067 mm) Cape gauge Wheel diameter 1,219 mm (48.0 in) Minimum curve 91.45 m (300 ft) Wheelbase 9,423 mm (30 ft 11.0 in)  • Bogie 2,819 mm (9 ft 3.0 in) Pivot centres 6,604 mm (21 ft 8.0 in) Length: ​  • Over couplers 13,310 mm (43 ft 8.0 in) Width 2,800 mm (9 ft 2.2 in) Height: ​  • Pantograph ♠ 3,859 mm (12 ft 7.9 in) ♥ 4,026 mm (13 ft 2.5 in)  • Body height ♠ 3,478 mm (11 ft 4.9 in) ♥ 3,618 mm (11 ft 10.4 in) Axle load 17,018 kg (37,518 lb) Loco weight 68,075 kg (150,080 lb) Power supply Catenary Current source Pantograph Traction motors Four MV 182R  • Rating 1 hour 224 kW (300 hp) Gear ratio 17:75 Train brakes Air & Vacuum Couplers AAR knuckle
Performance figures Maximum speed 40 km/h (25 mph) Power output 896 kW (1,202 hp) Tractive effort: ​  • Starting 176 kN (40,000 lbf)  • 1 hour 94 kN (21,000 lbf)  • Continuous 73 kN (16,000 lbf)
Career Operators South African Railways Driefontein GM Class Class ES Power class 3 kV DC Number in class 28 Numbers SAR E500-E501 (ex E96-E97), E503-E512 (ex E124-E133), E515-E526, Driefontein 1-4 Nicknames Studebaker Delivered 1936-1964 First run 1936 Withdrawn c. 1983

The South African Railways Class ES of 1936 was an electric locomotive.

In 1936, the South African Railways built two Class ES centre-cab electric shunting locomotives with a Bo-Bo wheel arrangement, based on the Class 1E mainline electric locomotive. Between then and 1964, more were acquired until a total of 24 Class ES locomotives were eventually in service. Four more were built new for industry in 1952 and 1957.

The Class ES was the fourth locomotive type to be designed and built in South Africa, after the Natal Government Railways 4-6-2TT Havelock of 1888, the Class 2C of 1910 and the Class 20 of 1935.

During 1935, it was decided to replace steam shunting locomotives with electric shunting units at Daimana (Danskraal) in Ladysmith. A design for a centre-cab electric shunting locomotive, based on the Class 1E mainline locomotive which was originally designed by Metropolitan-Vickers (Metrovick), was prepared by A.G. Watson, Chief Mechanical Engineer of the South African Railways (SAR) from 1929 to 1936, in collaboration with the SAR Electrical Department.

The first two Class ES locomotives were built new in Pietermaritzburg, where the bodywork was constructed in the SAR workshops. Two sets of spare Class 1E power bogies, complete with traction motors and gearing, were used. The wiring, control equipment and auxiliary machinery were installed at Daimana. These two units were initially numbered E96 and E97, but they were later renumbered to E500 and E501. They entered service at Daimana in 1936 as South Africa's first purpose-built electric shunting locomotives.

Even though it was not wholly a South African product with its imported Class 1E spare parts, the Class ES was the fourth recorded instance of locomotives designed and constructed in South African workshops, after the Natal Government Railways' engine Havelock of 1888, the Class 2C of 1910 and the Class 20 of 1935.

Over the next 28 years, more of these locomotives were built and by 1964 24 Class ES locomotives had been placed in service by the SAR. As can be expected in a locomotive type which was built by different manufacturers over a period of almost three decades, there are differences in appearance between locomotives.