South African Class H 4-10-2T

The South African Railways Class H 4-10-2T of 1899 was a steam locomotive from the pre-Union era in the Colony of Natal.

Between 1899 and 1903, the Natal Government Railways placed 101 tank steam locomotives with a 4-10-2 wheel arrangement in service. In 1912, after the establishment of the South African Railways, 93 of these Class C Reid Tenwheelers survived unmodified and were designated Class H.^[1][2][3]

Design

By 1898, increasing traffic on the new Natal Government Railways (NGR) mainline into the interior, with its sharp curves and severe 1 in 30 (3⅓%) gradients, necessitated double-heading of the NGR's Dübs A 4-8-2T locomotives on the heavier section of the Natal mainline between Estcourt and Mooirivier as a means to run longer trains to reduce occupation of the line. The requirement therefore arose for a tank locomotive which could haul at least one-and-a-half times as much as a Dübs A locomotive.^[2][3][4]

The limitations within which G.W. Reid, Locomotive Superintendent of the NGR at the time, had to meet this requirement were rather severe. The maximum axle load was not to exceed 14 long tons (14,220 kilograms) within the construction loading gauge of 13 feet (3,962 millimetres) high by 9 feet (2,743 millimetres) wide, while the locomotive had to be able to negotiate gradients of 1 in 30 (3⅓%), compensated for curves of 300 feet (91 metres) radius. The result was Reid's design of a 4-10-2 tank engine, the first locomotive in the world to use this wheel arrangement.^[2][3][4]

Manufacturers

Since there was no precedent for such an enormous Cape gauge tank locomotive, the design was the subject of some severe criticism and various objections were put forward against its introduction. It was therefore decided to order only one experimental locomotive from Dübs and Company. It was delivered in 1899 and numbered 149.^[4]

G.W. Reid

In 1900, the General Manager of the NGR reported that the trials of the 4-10-2T Reid locomo­tive had proven successful beyond anticipation and that the engine could haul a gross load of 200 long tons (203.2 tonnes) over the worst section of line with ease, 50% in excess of that taken by a Dübs A locomotive. As a result, orders were placed for another 100 of these locomo­tives between 1901 and 1903. The first 95 of these locomotives were built in four batches by Dübs and were numbered in the range from 150 to 244.^[2][4]

Since Dübs and a number of other Scottish locomotive builders were merged to form the North British Locomotive Company (NBL) while the locomotives were being built, the last five engines were delivered as having been built by the newly established NBL, numbered in the range from 245 to 249.^[4][5][6]

Classification

On the NGR, the locomotive type became known as the Reid Tenwheeler. When a locomotive classification system was introduced on the NGR, they were designated Class C.^[4][5][7]

Characteristics

To negotiate sharp curves, both the first and fifth pairs of coupled wheels were flangeless. The cylinders were arranged outside the plate frame, while the Richardson balanced type slide valves were placed between the frames. The locomotive used saturated steam and was equipped with Allan straight link valve gear, which was reversed by hand-wheel and quick screw gear. Allan valve gear was chosen chiefly because it required less space than the more usual Stephenson lifting link gear and was simpler in construction. The trailing Bissel truck was of the Cartazzi type which allowed the axle some lateral movement.^[2][3][4]

The leading bogie was controlled by two side-check springs and had 4 inches (102 millimetres) of side-play in each direction. This arrangement was later modified on some locomotives by substituting it with swing links. The portion of the driving crankpins for the connecting rod big-ends was turned 1 ¹⁄₂ inches (38 millimetres) eccentric to that of the coupling rods to obtain the longest possible piston stroke which the wheel diameter would permit, while keeping the throw of the coupling rod to a reasonable amount. Since the piston rod and crosshead was forged in one piece, the connecting rod small-end had to be forked.^[2][4]

The firebox, at 8 feet 11 ⁵⁄₈ inches (2,734 millimetres) long and 2 feet 4 ¹⁄₂ inches (724 millimetres) wide inside and arranged between the frames, was the longest ever used in South Africa.^[2]

Modifications

The main shortcoming of the Reid Tenwheeler was a tendency to derail while reversing, particularly over points, since the trailing coupled wheels were flangeless and tended to drop off the rails in the 1 in 7 turnouts which were in use at the time. This was overcome by increasing the tyre width from 6 inches (152 millimetres) to 7 inches (178 millimetres), after which the locomotives proved successful in service.^[2][4]

When some were withdrawn from mainline service and placed in branch line and shunting service where smaller radius curves were encountered, they were modified to 4-8-2T locomotives by removing the fifth pair of coupled wheels.^[3][4]

South African Railways

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.^[1][8]

In 1912, the 93 as yet unmodified Class C Reid Tenwheelers were designated Class H on the South African Railways (SAR) and renumbered in the range from 232 to 324. The modified 4-8-2T engines, also designated NGR Class C, were designated Class H2 on the SAR and renumbered in the range from 227 to 231. Three locomotives, NGR numbers 194, 195 and 214, had been scrapped prior to 1912 and did not come under the renumbering scheme.^[1][3][4]

The SAR Class H locomotives were gradually also modified to a 4-8-2T wheel arrangement. The first three of these, SAR numbers 240, 294 and 305, were renumbered again to 329, 330 and 331 respectively, but the rest retained their Class H engine numbers after modification. Their builders, works numbers and renumbering are listed in the table.^[1][4][6]

Service

The Reid Tenwheelers were initially employed on the lower section of the Natal mainline and worked both passenger and goods trains. Most of them continued to work there even after more powerful locomotives were placed in service. When the Corridor Train was introduced between Durban and Johannesburg in 1903, the Reid Tenwheelers worked the trains between Durban and Volksrust, but their limited coal and water capacity necessitated en route engine changes at Inchanga, Pietermaritzburg, Mooirivier, Ladysmith and Hattingspruit.^[2]

In the SAR era, some were relocated to De Doorns in the Cape Province for banking service up the Hex River Railpass. They had a long service life and some, modified to the 4-8-2T Mountain type, remained in service until 1977.^[3]

Other operators

Imperial Military Railways

In 1902, during the Second Boer War, the Imperial Military Railways (IMR) placed orders with Dübs and Company and Neilson, Reid and Company for altogether 35 locomotives of the Reid Tenwheeler type. In SAR service, these locomotives were designated Class H1 in 1912.^[2][3][4]

Industry

A final order for one new Reid Tenwheeler locomotive was placed by Witbank Collieries as late as 1927. The total of 137 locomotives which were built to this design was about double the number of all other 4-10-2 locomotives in use elsewhere in the world, all of which were tender locomotives which served mainly in the United States of America and Brazil.^[5]

Illustration

References

Wikimedia Commons has media related to South African Class H 4-10-2T.

Locomotives of Natal
4' 8½" gauge	Natal 0-4-0ST Durban Natal 0-4-0WT Natal Natal 4-4-0T Perseverance
3' 6" gauge	Durban's Congella Durban's Edward Innes Durban's John Milne Durban's Sir Albert NGR Class A 1905 NGR Class A 1910 NGR Class B 4-8-0 1904 NGR Class B 4-8-0 1910 NGR Class B 4-8-2 1906 NGR Class B 4-8-2 1909 NGR Class B 4-8-2 1910 NGR Class C 4-8-2T NGR Class C 4-10-2T NGR Class D NGR Class E NGR Class F NGR Class G NGR Class H 4-6-2T NGR Class H 4-6-4T NGR Class I 2-6-0 NGR Class I 2-6-2T NGR Class K 0-4-0ST NGR Class K 0-6-0ST NGR Class K 2-6-0T NGR Class L 4-8-0 NGR Durban & Pietermaritzburg NGR Havelock NGR Mallet 1909 NGR Mallet 1910
2' gauge	NGR Class N 1906 NGR Class N 1907 NGR Class N 1911
List of South African locomotive classes South African locomotive history

Locomotives of South Africa
Steam	7' ¼" gauge East London 0-4-0VB Table Bay 0-4-0ST Table Bay 0-4-0T Table Bay 0-4-0WT 4' 8½" gauge Cape 0-4-0T Blackie Cape 0-4-2 Cape 2-4-0T CGR 0-4-0ST Aid Natal 0-4-0ST Durban Natal 0-4-0WT Natal Natal 4-4-0T Perseverance 3' 6" gauge Tank engines CGR 0-4-0ST 1873 CGR 0-4-0ST 1874 CGR 0-4-0ST 1881 CGR 0-4-0ST 1881 Coffee Pot CGR 0-6-0ST CGR 0-6-0T CGR 2-6-0ST 1900 CGR 2-6-0ST 1902 CGR 1st Class 0-4-0ST 1875 CGR 1st Class 0-4-0ST 1876 CGR 1st Class 2-6-0ST CGR 1st Class 4-4-0T CGR 2nd Class 4-4-0T CGR 3rd Class 2-6-0T CGR Railmotor CSAR Class C CSAR Class E CSAR Rack 4-6-4RT CSAR Railmotor Durban's Congella Durban's Edward Innes Durban's John Milne Durban's Sir Albert Port Elizabeth 0-4-0ST Kowie Railway 0-6-0T Kowie Railway 4-4-0T Metropolitan & Suburban 4-6-2T NGR 2-6-0T Durban & Pietermaritzburg NGR Class I 2-6-2T NGR Class K 0-4-0ST NGR Class K 0-6-0ST NGR Class K 2-6-0T NZASM 10 Tonner NZASM 13 Tonner NZASM 14 Tonner NZASM 18 Tonner NZASM 19 Tonner NZASM 32 Tonner NZASM 40 Tonner PPR 26 Tonner PPR 35 Tonner Portuguese SAR Class A SAR Class B SAR Class C SAR Class C1 SAR Class C2 SAR Class D SAR Class E SAR Class F SAR Class G SAR Class H SAR Class H1 SAR Class H2 SAR Class J SAR Class K SAR Railmotor SAR Dock 0-4-0ST SAR Dock 0-4-0T SWA 2-8-0T 3' 6" gauge Tender engines CGR 1st Class 2-6-0 1876 BP CGR 1st Class 2-6-0 1876 Kitson CGR 1st Class 2-6-0 1879 CGR 1st Class 2-6-0 1891 CGR 1st Class 4-4-0 CGR 1st Class 4-4-0TT CGR 2nd Class 2-6-2TT CGR 3rd Class 4-4-0 1883 CGR 3rd Class 4-4-0 1884 CGR 3rd Class 4-4-0 1889 CGR 3rd Class 4-4-0 1898 CGR 3rd Class 4-4-0 1901 CGR 3rd Class 4-4-0 1903 CGR 4th Class 4-4-2 CGR 4th Class 4-6-0TT 1880 CGR 4th Class 4-6-0TT 1882 CGR 4th Class 4-6-0TT 1882 Joy CGR 4th Class 4-6-0TT 1884 CGR 5th Class 4-6-0 1890 CGR 5th Class 4-6-0 1891 NGR Havelock NGR Class I SAR Class Exp 1 SAR Class Exp 2 SAR Class Exp 3 SAR Class Exp 4 SAR Class Exp 5 SAR Class Exp 6 SAR Class S SAR Class S1 SAR Class S2 SAR Class 1 SAR Class 1A SAR Class 1B SAR Class 2 SAR Class 2C SAR Class 3 SAR Class 3A SAR Class 3B SAR Class 4 SAR Class 4A SAR Class 5 SAR Class 5A SAR Class 5B SAR Class 6 SAR Class 6A SAR Class 6B SAR Class 6C SAR Class 6D SAR Class 6E SAR Class 6F SAR Class 6G SAR Class 6H SAR Class 6J SAR Class 6K SAR Class 6L SAR Class 6Y SAR Class 6Z SAR Class 7 SAR Class 7A SAR Class 7B SAR Class 7C SAR Class 7D SAR Class 7E SAR Class 7F SAR Class 8 SAR Class 8A SAR Class 8B SAR Class 8C SAR Class 8D SAR Class 8E SAR Class 8F SAR Class 8R SAR Class 8X SAR Class 8Y SAR Class 8Z SAR Class 9 SAR Class 10 SAR Class 10A SAR Class 10B SAR Class 10C SAR Class 10D SAR Class 11 SAR Class 12 SAR Class 12A SAR Class 12B SAR Class 13 SAR Class 14 SAR Class 14A SAR Class 14B SAR Class 14C 1st SAR Class 14C 2nd SAR Class 14C 3rd SAR Class 14C 4th SAR Class 15 SAR Class 15A SAR Class 15B SAR Class 15C SAR Class 15CA SAR Class 15E SAR Class 15F SAR Class 16 SAR Class 16A SAR Class 16B SAR Class 16C SAR Class 16D SAR Class 16DA 1928 SAR Class 16DA 1930 SAR Class 16E SAR Class 17 SAR Class 18 SAR Class 19 SAR Class 19A SAR Class 19B SAR Class 19C SAR Class 19D SAR Class 20 SAR Class 21 SAR Class 23 SAR Class 24 SAR Class 25 SAR Class 25NC SAR Class 26 SAR Katanga SWA 2-8-0 3' 6" gauge Articulated engines CGR Fairlie CGR Kitson-Meyer SAR Class FC SAR Class FD SAR Class GA SAR Class GB SAR Class GC SAR Class GCA SAR Class GD SAR Class GDA SAR Class GE SAR Class GEA SAR Class GF SAR Class GG SAR Class GH SAR Class GK SAR Class GL SAR Class GM SAR Class GMA SAR Class GO SAR Class HF SAR Class KM SAR Class MA SAR Class MB SAR Class MC SAR Class MC1 SAR Class MD SAR Class ME SAR Class MF SAR Class MG SAR Class MH SAR Class MJ SAR Class MJ1 SAR Class U 2' 6" gauge Cape Copper John King & Miner Cape Copper Britannia Cape Copper Caledonia Cape Copper Clara Cape Copper Condenser Cape Copper Scotia Namaqua Copper Pioneer Walvis Bay 2-4-2T Hope 2' & 600mm gauges ACR Class NG-G16A CGR NG 0-4-0T CGR NG 0-6-0T CGR NG 4-6-2T CGR Type A 2-6-4T CGR Type C 0-4-0T NGR Class N 4-6-2T SAR Dutton SAR NG 0-4-0T SAR Class NG1 SAR Class NG2 SAR Class NG3 SAR Class NG4 SAR Class NG5 SAR Class NG6 SAR Class NG7 SAR Class NG8 SAR Class NG9 SAR Class NG10 SAR Class NG-G11 SAR Class NG-G12 SAR Class NG-G13 SAR Class NG-G14 SAR Class NG15 SAR Class NG-G16 SWA Class Ha SWA Class Hb SWA Class Hc SWA Class Hd SWA Jung SWA Zwillinge
Electric	Amcoal Class E38 SAR Class ES SAR Class ES1 SAR Class Exp-AC SAR Class 1E SAR Class 2E SAR Class 3E SAR Class 4E SAR Class 5E s1 SAR Class 5E s2 SAR Class 5E s3 SAR Class 5E1 s1 SAR Class 5E1 s2 SAR Class 5E1 s3 SAR Class 5E1 s4 SAR Class 5E1 s5 SAR Class 6E SAR Class 6E1 s1 SAR Class 6E1 s2 SAR Class 6E1 s3 SAR Class 6E1 s4 SAR Class 6E1 s5 SAR Class 6E1 s6 SAR Class 6E1 s7 SAR Class 6E1 s8 SAR Class 6E1 s9 SAR Class 6E1 s10 SAR Class 6E1 s11 SAR Class 7E SAR Class 7E1 SAR Class 7E2 s1 SAR Class 7E2 s2 SAR Class 7E3 s1 SAR Class 7E3 s2 Spoornet Class 7E4 SAR Class 8E SAR Class 9E s1 SAR Class 9E s2 SAR Class 10E SAR Class 10E1 s1 Spoornet Class 10E1 s2 SAR Class 10E2 SAR Class 11E SAR Class 12E Spoornet Class 14E Spoornet Class 14E1 TFR Class 15E Spoornet Class 16E Spoornet Class 17E Spoornet Class 18E s1 TFR Class 18E s2 TFR Class 19E TFR Class 20E TFR Class 21E TFR Class 22E
Gas-electric	SAR Gas-electric
Diesel	3' 6" gauge Diesel-electric PRASA Class Afro 4000 SAR Class DS SAR Class DS1 SAR Class 31-000 SAR Class 32-000 SAR Class 32-200 SAR Class 33-000 SAR Class 33-200 SAR Class 33-400 SAR Class 34-000 SAR Class 34-200 SAR Class 34-400 SAR Class 34-500 SAR Class 34-600 SAR Class 34-800 SAR Class 34-900 SAR Class 35-000 SAR Class 35-200 SAR Class 35-400 SAR Class 35-600 TFR Class 35-800 SAR Class 36-000 SAR Class 36-200 SAR Class 37-000 Spoornet Class 39-000 TFR Class 39-200 TFR Class 43-000 TFR Class 44-000 2' gauge Diesel-electric SAR Class 91-000 3' 6" gauge Diesel-hydraulic SAR Class 61-000 3' 6" gauge Electro-diesel Spoornet Class 38-000
List of South African locomotive classes South African locomotive numbering and classification