South African Class H2 4-8-2T

NGR Class C 4-8-2T South African Class H2 4-8-2T
Class H2 no. 329 at Masons Mill, 29 March 1979 Ex NGR Class C 4-10-2T no. 157 Ex SAR Class H 4-10-2T no. 240
Type and origin Power type Steam Designer Natal Government Railways (G.W. Reid) Builder Dübs and Company Natal Government Railways South African Railways Serial number Dübs 4047, 4060, 4063, 4117, 4271, 4273, 4315, 4325 Model NGR Reid Tenwheeler Build date c. 1909-1912 Total produced 8
Specifications Configuration: ​  • Whyte 4-8-2T (Mountain)  • UIC 2'D1'n2t Driver 2nd coupled axle Gauge 3 ft 6 in (1,067 mm) Cape gauge Leading dia. 25 3⁄4 in (650 mm) Coupled dia. 45 in (1,100 mm) Trailing dia. 25 3⁄4 in (650 mm) Minimum curve 300 ft (91 m) radius Wheelbase 30 ft 6 in (9,296 mm)  • Leading 5 ft 4 in (1,626 mm)  • Coupled 12 ft 6 in (3,810 mm) Length: ​  • Over couplers 37 ft 6 in (11,430 mm) Height 12 ft 6 in (3,810 mm) Axle load 13 LT (13,210 kg)  • Leading 10 LT 4 cwt 2 qtr (10,390 kg)  • Coupled 13 LT (13,210 kg)  • Trailing 6 LT (6,096 kg) Adhesive weight 52 LT (52,830 kg) Loco weight 68 LT (69,090 kg) Fuel type Coal Fuel capacity 4 LT (4.1 t) Water cap 1,880 imp gal (8,550 l) Firebox type Round-top  • Firegrate area 21 sq ft (2.0 m2) Boiler: ​  • Pitch 6 ft 10 in (2,083 mm)  • Diameter 4 ft 7 7⁄8 in (1,419 mm)  • Tube plates 10 ft 4 in (3,150 mm)  • Small tubes 287: 1 3⁄4 in (44 mm) Boiler pressure 175 psi (1,207 kPa) Safety valve Ramsbottom Heating surface 1,494 sq ft (138.8 m2)  • Tubes 1,359 sq ft (126.3 m2)  • Firebox 135 sq ft (12.5 m2) Cylinders Two Cylinder size 19 in (483 mm) bore 27 in (686 mm) stroke Valve gear Allan Couplers Johnston link-and-pin AAR knuckle (1930s)
Performance figures Tractive effort 28,430 lbf (126.5 kN) @ 75%
Career Operators Natal Government Railways South African Railways Class NGR Class C, SAR Class H2 Number in class 8 Numbers NGR 170, 173, 175, 217 & 240 SAR 227-231, 329-331 Delivered c. 1909-1912 First run 1909 Withdrawn 1977
The leading coupled axle had flangeless wheels

The South African Railways Class H2 4-8-2T of 1909 was a steam locomotive from the pre-Union era in the Colony of Natal.

Between 1899 and 1903, the Natal Government Railways placed 101 4-10-2 tank steam locomotives in service. By 1910, five of them had been converted to a 4-8-2T wheel arrangement and in 1912, when the South African Railways classification and renumbering of locomotives took place, these five were designated Class H2.

The requirement for a tank locomotive which could haul at least one-and-a-half times as much as a Dübs A 4-8-2T locomotive on the mainline of the Natal Government Railways (NGR) resulted in the design of a 4-10-2 tank locomotive by NGR Locomotive Superintendent G.W. Reid. Altogether 101 of these locomotives were built by Dübs and Company and North British Locomotive Company, delivered between 1899 and 1903 and numbered in the range from 149 to 249.

On the NGR, the locomotive type became known as the Reid Tenwheeler, until a classification system was introduced in 1905 or 1906 and they were designated the NGR Class C.

When the Reid Tenwheelers began to be withdrawn from mainline service and placed 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. By the end of 1908, these locomotives were all still shown on the NGR roster as 4-10-2T locomotives, but from c. 1909 some of them were gradually converted to a 4-8-2T wheel arrangement by removing the fifth set of coupled wheels and blanking off the resulting opening in the frame.

When the Union of South Africa was established on 31 May 1910, the three Colonial government railways (Cape Government Railways, NGR and Central South African Railways) were united under a single administration to control and administer the railways, ports and harbours of the Union. Although the South African Railways and Harbours came into existence in 1910, the actual classification and renumbering of all the rolling stock of the three constituent railways were only implemented with effect from 1 January 1912.