South African Class H2 4-8-2T

South African Class H2 4-8-2T
Class H2 329 at Masons Mill, Pietermaritzburg, 29 March 1979
Ex NGR 4-10-2T Reid Tenwheeler 157
Ex SAR 4-10-2T Class H 240
Power type Steam
Designer Natal Government Railways
Builder Dübs and Company
North British Locomotive Company
Serial number Dübs 3835, 4040-4064, 4118-4141, 4254-4278, 4310-4329[1]
NBL 15723-15727[2]
Model Reid Tenwheeler
Build date 1899-1903
Total produced 101
Rebuilder Natal Government Railways
South African Railways
Number rebuilt 5 by NGR, 3 by SAR
Configuration 4-8-2T "Mountain"
Gauge 3 ft 6 in (1,067 mm) Cape gauge
Leading wheel
diameter		 25.75 in (654 mm)
Driver diameter 45 in (1,140 mm)
Trailing wheel
diameter		 25.75 in (654 mm)
Minimum curve 300 ft (91.440 m) radius
Wheelbase 30 ft 6 in (9.296 m) total
5 ft 4 in (1.626 m) pilot
12 ft 6 in (3.810 m) coupled
Length 37 ft 6 in (11.430 m)
Height 12 ft 6 in (3.810 m)
Axle load 13 long tons (13.2 t) per driver
Weight on drivers 52 long tons (52.8 t)
Locomotive weight 68 long tons (69.1 t)
Fuel type Coal
Fuel capacity 4 long tons (4.1 t)
Water capacity 1,880 imp gal (8,500 l)
Boiler 4 ft 7.875 in (1.419 m) int dia
10 ft 4 in (3.150 m) int length
6 ft 10 in (2.083 m) pitch
Boiler pressure 175 psi (1,210 kPa)
Firegrate area 21 sq ft (1.951 m2)
Heating surface:
Tubes		 287 tubes 1.75 in (44.5 mm) dia
1,359 sq ft (126.255 m2)
Heating surface:
Firebox		 135 sq ft (12.542 m2)
Heating surface:
Total		 1,494 sq ft (138.797 m2)
Cylinders Two
Cylinder size 19 in (483 mm) bore
27 in (686 mm) stroke
Valve gear Allan
Tractive effort 28,430 lbf (126.5 kN) at 75% boiler pressure[1][3]
Career Natal Government Railways
South African Railways
Class Class H2
Number in class 8
Number NGR 170, 173, 175, 217 & 240
SAR 227-231, 329-331[4]
Delivered 1901-1903
First run 1901
Withdrawn 1977
Disposition Retired

Between 1899 and 1903 the Natal Government Railways placed one hundred and one 4-10-2T tank steam locomotives in service. By 1910 five of them had been converted to a 4-8-2T wheel arrangement and in 1912, with the establishment of the South African Railways, these five were designated Class H2.[4][5]

Contents

Origin

The requirement for a tank locomotive that could haul at least one and a half times as much as a Dübs A 4-8-2T locomotive on the main line of the Natal Government Railways (NGR) resulted in the design of a 4-10-2T tank locomotive by NGR Locomotive Superintendent G.W. Reid. Altogether one hundred and one of these locomotives were built by Dübs and Company and North British Locomotive Company, delivered between 1899 and 1903 and numbered 149 to 249. On the NGR the locomotive type became known as the "Reid Tenwheeler".[1][5][6]

Modification

When the Reid Tenwheelers began to be withdrawn from main line service and put in branch line and shunting service where smaller radius curves were encountered, it was found that the ten-coupled wheelbase was prone to derailment in many goods yards. These locomotives were therefore gradually converted to a 4-8-2T wheel arrangement by removing the fifth set of drivers and blanking off the resulting opening in the frame.[5]

South African Railways

By the time the South African Railways (SAR) was established in 1912 and the locomotives of the three component colonial railways were renumbered and reclassified onto the SAR roster, five locomotives were already modified to a 4-8-2T wheel arrangement. These were NGR numbers 170, 173, 175, 217 and 240, all built by Dübs between 1901 and 1903. They were classified as Class H2 and were renumbered 227 to 231 on the SAR roster.[4][5][7]

Of the remaining ninety-six unmodified 4-10-2T Reid Tenwheeler locomotives, three had already been scrapped by 1912. The rest were classified as Class H and were renumbered 232 to 324 on the SAR roster.[1][4]

After 1912 these Class H locomotives were gradually also modified to a 4-8-2T wheel arrangement. The first three to be modified after being rostered in SAR service, numbers 240, 294 and 305, were reclassified to Class H2 as well and were renumbered once again, to 329, 330 and 331 respectively. The rest retained their Class H numbers even after modification. The builders, works numbers and renumbering of these eight Class H2 locomotives are set out in the table.[1]

Service

The Class H2 was employed extensively in shunting service in many parts of the country, together with the Class H1. Because of their light axle loading, the last ones to remain in service were retained for use on the Bluff in Durban until 1977.[5]

Gallery

The main picture shows the retired Class H2 329, ex NGR 157, one of the first three Reid Tenwheelers to be modified to a 4-8-2T Class H2 after having originally being taken onto the SAR roster as an unmodified 4-10-2T Class H, number 240. It was earmarked for preservation and photographed on 29 March 1979, staged at Masons Mill in Pietermaritzburg.

See also

References

  1. ^ a b c d e Holland, D.F. (1971). Steam Locomotives of the South African Railways, Volume 1: 1859-1910 (1st ed.). Newton Abbott, Devon: David & Charles. pp. 92-95, 123-124. ISBN 0715353829. 
  2. ^ North British Locomotive Company works list, compiled by Austrian locomotive historian Bernhard Schmeiser
  3. ^ South African Railways and Harbours Locomotive Diagram Book, 2’0” & 3’6” Gauge Steam Locomotives, 15 August 1941, pp21 & 21A, as amended
  4. ^ a b c d Classification of S.A.R. Engines with Renumbering Lists, issued by the Chief Mechanical Engineer’s Office, Pretoria, January 1912, pp. 7, 11, 13, 23 (Reprinted in April 1987 by SATS Museum, R.3125-6/9/11-1000)
  5. ^ a b c d e Paxton, Leith; Bourne, David (1985). Locomotives of the South African Railways (1st ed.). Cape Town: Struik. pp. 10-11, 31-33. ISBN 0869772112. 
  6. ^ Durrant, A E (1989). Twilight of South African Steam (1st ed.). Newton Abbott, London: David & Charles. p. 15. ISBN 0715386387. 
  7. ^ Holland, D.F. (1972). Steam Locomotives of the South African Railways, Volume 2: 1910-1955 (1st ed.). Newton Abbott, Devon: David & Charles. p. 136. ISBN 0715354272.