South African Class ES1 explained

South African Class ES1
Powertype:Electric
Designer:English Electric
Builder:English Electric
Buildmodel:SAR ES1
Builddate:1924
Aarwheels:B
Uicclass:Bo
Britishclass:Bo
Wheeldiameter:380NaN0
Wheelbase:10feet
Over Couplers:24feet
Over Bufferbeams:220NaN0
Height:100NaN0
Axleload:12lt
Locoweight:24lt
Electricsystem:235 V 196 A, 208 cell battery
Collectionmethod:N/A
Tractionmotors:Two
Gear Ratio:5.4:1
Coupling:Johnston link-and-pin
AAR knuckle (1930s)
Poweroutput:500NaN0
T/E 1 Hr:8500lbf
Operator:South African Railways
ESKOM
Operatorclass:Class ES1
Numinclass:1
Fleetnumbers:E123, renumbered E502
Nicknames:Queen Mary
Deliverydate:1924
Firstrundate:1924
Withdrawndate:1978

The South African Railways Class ES1 of 1924 was an electric locomotive.

In 1924, the South African Railways placed a single Class ES1 battery-powered shunting locomotive in service at the construction site of the Colenso power station. In 1927, the power station and the locomotive were sold to the Electricity Supply Commission and in 1937 the locomotive was purchased back for use at the Daimana (Danskraal) locomotive depot.[1]

Manufacturer

During the electrification of the Glencoe to Pietermaritzburg section of the Natal mainline, a mountainous single-track line which carried heavy mineral traffic towards the port of Durban on an alignment with severe gradients and tight curves, the Colenso power station was built by the South African Railways (SAR) to supply the power for this line.[2]

A single battery-powered electric shunting locomotive, the only battery-powered locomotive to ever see service on the SAR, was purchased from English Electric in 1924 for use at the power station construction site.[3]

Characteristics

The centre-cab locomotive had a Bo wheel arrangement, the two axles being driven by two 37kW traction motors, operating at 235 volts and powered by a 208 cell nickel-iron alkali type battery with a 435 amp-hour capacity.

Service

The locomotive remained in service at the Colenso power station after 1927, when the power station and all its equipment, including the battery locomotive, was sold to the Electricity Supply Commission (ESKOM), the state-owned South African national power corporation.

In 1937, the locomotive was purchased back from ESKOM by the SAR, designated Class ES1 with unit number E123 and stationed at the Daimana (Danskraal) locomotive depot at Ladysmith where it was used as shop shunting engine to move cold steam locomotives and dead electric units. Nicknamed Queen Mary, it was later renumbered to E502. It remained in service at Danskraal until it was withdrawn from service in 1978.[1]

Notes and References

  1. Espitalier, T.J.; Day, W.A.J. (1946). The Locomotive in South Africa – A Brief History of Railway Development. Chapter VII – South African Railways (Continued). South African Railways and Harbours Magazine, April 1946. p. 296.
  2. South African Railways Power Plant. Electric Railway Journal. 9 December 1922. 60. 24. 914. 15 September 2010.
  3. South African Railways Index and Diagrams Electric and Diesel Locomotives, 2'0" & 3'6" Gauge, circa 1940, as amended