South African Class 6B 4-6-0

South African Class 6B 4-6-0
ex CGR 6th Class 4-6-0

Ex CGR 6th Class no. 206, SAR Class 6B no. 494, c. 1930
Type and origin
Power type Steam
Designer Cape Government Railways
Builder Dübs and Company
Neilson and Company
Neilson, Reid and Company
Serial number Dübs 3467-3468, 3472-3474 [1]
Neilson 5120-5125, 5128-5129, 5131-5159
Neilson, Reid 5273-5279, 5319-5324 [2]
Model CGR 6th Class
Build date 1897-1898 [1]
Total produced 55
Specifications
Configuration 4-6-0 "Tenwheeler"
Gauge 3 ft 6 in (1,067 mm) Cape gauge
Leading wheel
diameter		 28.5 in (724 mm)
Driver diameter 54 in (1,370 mm)
Wheelbase Total: 46 ft 6.25 in (14.180 m)
Engine:
5 ft 5.5 in (1.664 m) bogie
11 ft (3.353 m) coupled
20 ft 3.75 in (6.191 m) total
Tender:
4 ft 7 in (1.397 m) bogie
16 ft 1 in (4.902 m) total
Length 53 ft 8.75 in (16.377 m)
Height 12 ft 10 in (3.912 m) as built
12 ft 10.75 in (3.931 m) Belpaire
Frame Plate frame
Axle load 12.15 long tons (12.3 t) on 3rd driver as built
13.4 long tons (13.6 t) per driver, Belpaire
Weight on drivers 34.4 long tons (35.0 t) as built
40.2 long tons (40.8 t) Belpaire
Locomotive weight 46.25 long tons (47.0 t) as built
51.075 long tons (51.9 t) Belpaire
Locomotive and tender
combined weight		 77.4 long tons (78.6 t) as built
82.225 long tons (83.5 t) Belpaire
Tender type XE - XC, XC1, XD, XE, XE1, XF, XF1, XF2, XJ, XM, XN1, XM2, XM3, XM4 permitted
* 2 axle bogies
* 34 in (864 mm) wheels
* Length 23 ft 0.125 in (7.014 m)
Fuel type Coal
Fuel capacity 8 long tons (8.1 t)
Water capacity 2,850 imp gal (13,000 l)
Boiler As built:
4 ft 4 in (1.321 m) inside diameter
11 ft 2.125 in (3.407 m) inside length
6 ft 8 in (2.032 m) pitch
Belpaire:
4 ft 9 in (1.448 m) inside diameter
11 ft 2.125 in (3.407 m) inside length
7 ft (2.134 m) pitch
Boiler pressure 180 psi (1,240 kPa)
Firegrate area 17 sq ft (1.579 m2) as built
16.6 sq ft (1.542 m2) Belpaire
Heating surface:
– Tubes		 As built:
185 tubes 1.875 in (47.6 mm) diameter
1,015 sq ft (94.297 m2)
Belpaire:
220 tubes 2 in (50.8 mm) diameter
1,287.5 sq ft (119.613 m2)
– Firebox 101 sq ft (9.383 m2) as built
111 sq ft (10.312 m2) Belpaire
– Total 1,116 sq ft (103.680 m2) as built
1,398.5 sq ft (129.925 m2) Belpaire
Cylinders Two
Cylinder size 17 in (432 mm) bore
26 in (660 mm) stroke
Valve gear Stephenson
Performance figures
Tractive effort 18,780 lbf (83.5 kN) at 75% pressure [3]
Career
Operator(s) Cape Government Railways
Imperial Military Railways
Benguela Railway
South African Railways
Sudan Railways
Class CGR 6th Class, SAR Class 6B
Number in class 51
Number(s) CGR 202-233, 577-584, 587-593, 595-600, 663-664
IMR C502, C504-C508, C512
Benguela 22-25
SAR 490-540 [1][4][5]
Sudan M711-M712 [6]
Delivered 1897-1898
First run 1897
Withdrawn 1973 [7]

The South African Class 6B 4-6-0 of 1897 is a South African steam locomotive from the pre-Union era in the Cape Colony.

In 1897 and 1898 the Cape Government Railways placed a third batch of fifty-five 6th Class 4-6-0 steam locomotives in service, thirty-two on its Western System, twenty-one on its Midland System and two on its Eastern System. During the Second Freedom War seven were transferred to the Imperial Military Railways on loan, and in 1907 four were sold to the Benguela Railway in Angola. In 1912, when the remaining fifty-one locomotives were assimilated into the South African Railways, they were renumbered and reclassified to Class 6B. During World War II two of them were sold to the Sudan Railways.[1][4][7]

Manufacturers

The 6th Class 4-6-0 passenger steam locomotive was designed at the Salt River works of the Cape Government Railways (CGR) at the same time as the 7th Class, both according to the specifications of Michael Stephens, then Chief Locomotive Superintendent of the CGR, and under the supervision of H.M. Beatty, then Locomotive Superintendent of the Cape Western System. Whereas the Class 7 was conceived primarily as a goods locomotive, the 6th Class was intended to be its fast passenger service counterpart.[1]

The fifty-five locomotives in the third group were built between 1897 and 1898 by Dübs and Company and Neilson and Company. While they were being built, in 1898, the firm of Neilson and Company changed its name to Neilson, Reid and Company. Five of these locomotives were built by Dübs and of the remaining fifty, thirty-seven were delivered as built by Neilson and the last thirteen as built by Neilson, Reid.[1]

All five Dübs-built locomotives, numbered in the range from 577 to 581, and the thirteen Neilson, Reid-builts, numbered in the ranges from 587 to 593 and 595 to 600, went to the Midland System. Of the thirty-seven Neilson-builts, thirty-two went to the Western System, numbered in the range from 202 to 233, three to the Midland System, numbered in the range from 582 to 584, and two to the Eastern System, numbered 663 and 664. Their respective works numbers and CGR engine numbers are tabulated below.[1]

These locomotives were to all intents and purposes identical to the previous fifty that became the Class 6A, except that they had Type XE bogie tenders instead of the six wheeled Type YC tenders that were used with the second group of 6th Class locomotives.[1]

Class 6 sub-classes

The Union of South Africa was established on 31 May 1910, in terms of the South Africa Act. One of the clauses in the Act required that the three Colonial Government railways, the CGR, the Natal Government Railways and the Central South African Railways, also be united under one single administration to control and administer the railways, ports and harbours of the Union. While the South African Railways (SAR) came into existence in 1910, the actual classification and renumbering of all the rolling stock of the three constituent railways required careful planning and was only implemented with effect from 1 January 1912.[4][8]

In 1912 all but four of these fifty-five locomotives were assimilated into the SAR, reclassified to Class 6B and renumbered in the range from 490 to 540.[3][4][5]

The rest of the CGR’s 6th Class locomotives, together with those Class 6-L1 to 6-L3 locomotives that were inherited by the Central South African Railways (CSAR) from the Oranje-Vrijstaat Gouwerment-Spoorwegen (OVGS) via the Imperial Military Railways (IMR), were grouped into thirteen more sub-classes by the SAR. The 4-6-0 locomotives became SAR Classes 6, 6A, 6C to 6H and 6J to 6L, the 2-6-2 locomotives became Class 6Y and the 2-6-4 locomotives became Class 6Z.[3][4][5]

Modifications

Several of the CSAR’s Class 6-L1 to 6-L3 locomotives had been modified by P.A Hyde, Chief Mechanical Engineer (CME) of the CSAR, by having their round top fireboxes replaced with larger Belpaire fireboxes and by having larger, more sheltered cabs installed. This conversion improved their performance tremendously and resulted in several of the Class 6, 6A and 6B locomotives being similarly modified by the SAR in later years, but without altering their classifications.[7]

During the 1930s many of them were modified once again, when the CME of the SAR at the time, A.G. Watson, displayed his aversion to Belpaire fireboxes and reboilered them with round-topped fireboxes again, but while retaining the larger cabs. Once again, they retained their classifications.[3][7]

Service

Imperial Military Railways

Seven of these locomotives saw service with the IMR during the Second Freedom War, on loan from the CGR and temporarily renumbered for the duration of the war.[1]

South African Railways

The 6th Class series of locomotives were introduced primarily as passenger locomotives, but when the class became displaced by larger and more powerful locomotive classes, it literally became a "Jack-of-all-trades" that proved itself as one of the most useful and successful locomotive classes ever to be designed at the Salt River shops. It went on to see service in all parts of the country except Natal and on all types of traffic.[1]

Benguela Railway

In 1907 four of these locomotives were sold to the Benguela Railway (Caminho de Ferro de Benguela – CFB) in Angola and these therefore did not see SAR service. In the mid-1930s, in order to ease maintenance, modifications were made to the running boards and brake gear of the CFB locomotives. The former involved mounting the running boards higher, thereby getting rid of the driving wheel fairings. This gave the locomotives a much more American rather than British appearance.[6][9]

Sudan Railways

During World War II sixteen of the Classes 6 to 6D were transferred to the Middle East to assist with the war effort during the North African Campaign. The two Class 6B locomotives in this group were numbers 534 and 538. They were sold to the Sudan Railways Corporation in 1942 and renumbered M711 and M712 in the same order as their former SAR engine numbers.[1][7][10]

Renumberings

During their long service lives some of the Class 6A locomotives underwent multiple renumberings. All were initially numbered into the CGR’s three systems, in the number ranges from 202 to 233 on the Western System, 577 to 584, 587 to 593 and 595 to 600 on the Midland System, and 663 and 664 on the Eastern System. The seven locomotives loaned to the IMR were renumbered C502, C504 to C508 and C512 for the duration of their military service, while the four sold to Angola became the Benguela Railway's numbers 22 to 25.[1]

With regard to the four Benguela locomotives, sources are inconclusive about the renumbering in respect of which particular CGR locomotive became which particular CFB locomotive and the numbers as listed were arrived at by a process of elimination.[6]

In 1912 the remaining fifty-one locomotives were renumbered in the number range from 490 to 540 on the SAR. The table reflects all these renumberings as well as their builders and works numbers.[1][2][4][5]

Service illustrated

The main picture shows Neilson-built ex CGR Western System 6th Class no. 206, later renumbered to SAR Class 6B no. 494 and reboilered with a Belpaire firebox, on the old Cape Town turntable. The locomotives in the pictures below all have round-top fireboxes.

See also

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 1.10 1.11 1.12 Holland, D.F. (1971). Steam Locomotives of the South African Railways, Volume 1: 1859-1910 (1st ed.). Newton Abbott, Devon: David & Charles. pp. 46–47, 57. ISBN 978-0-7153-5382-0.
  2. ↑ 2.0 2.1 Neilson, Reid works list, compiled by Austrian locomotive historian Bernhard Schmeiser
  3. ↑ 3.0 3.1 3.2 3.3 South African Railways and Harbours Locomotive Diagram Book, 2’0” & 3’6” Gauge Steam Locomotives, 15 August 1941, as amended
  4. ↑ 4.0 4.1 4.2 4.3 4.4 4.5 Classification of S.A.R. Engines with Renumbering Lists, issued by the Chief Mechanical Engineer’s Office, Pretoria, January 1912, pp. 8, 12, 14, 30-31 (Reprinted in April 1987 by SATS Museum, R.3125-6/9/11-1000)
  5. ↑ 5.0 5.1 5.2 5.3 Holland, D.F. (1972). Steam Locomotives of the South African Railways, Volume 2: 1910-1955 (1st ed.). Newton Abbott, Devon: David & Charles. pp. 137–138. ISBN 978-0-7153-5427-8.
  6. ↑ 6.0 6.1 6.2 Information supplied by Peter Bagshawe
  7. ↑ 7.0 7.1 7.2 7.3 7.4 Paxton, Leith; Bourne, David (1985). Locomotives of the South African Railways (1st ed.). Cape Town: Struik. pp. 41–44. ISBN 0869772112.
  8. ↑ The South African Railways - Historical Survey. Editor George Hart, Publisher Bill Hart, Sponsored by Dorbyl Ltd., Published c. 1978, p. 25.
  9. ↑ British Overseas Railways Historical Trust, Journal No. 8 & 9
  10. ↑ Class 6 to 6D sold to Sudan Railways during the WWII North African Campaign, list compiled by Austrian locomotive historian Reimar Holzinger