South African Class 6A 4-6-0

CGR 6th Class 4-6-0 1896
South African Class 6A 4-6-0

CGR no. 182, IMR no. C509, SAR no. 462, at De Aar, 15 April 1978
Type and origin
♠ Original locomotive, as built
♥ Locomotive equipped with Belpaire firebox
Power type Steam
Designer Cape Government Railways
(H.M. Beatty)
Builder Dübs and Company
Sharp, Stewart and Company
Serial number Dübs:
3330, 3332-3335, 3337, 3345-3347, 3437-3439, 3441-3447, 3449-3456, 3460-3466, 3469-3471, 3475-3476
Sharp Stewart:
4116-4119, 4122-4127, 4144
Model CGR 6th Class
Build date 1895-1897
Total produced 50
Specifications
Configuration 4-6-0 (Tenwheeler)
Driver 2nd coupled axle
Gauge 3 ft 6 in (1,067 mm) Cape gauge
Leading dia. 28 1⁄2 in (724 mm)
Coupled dia. 54 in (1,372 mm)
Tender wheels 37 in (940 mm)
Wheelbase 42 ft 5⁄8 in (12,817 mm)
 • Engine 20 ft 3 3⁄4 in (6,191 mm)
 • Leading 5 ft 5 1⁄2 in (1,664 mm)
 • Coupled 11 ft (3,353 mm)
 • Tender 10 ft (3,048 mm)
Wheel spacing
(Assymetrical)		 1-2: 4 ft 9 in (1,448 mm)
2-3: 6 ft 3 in (1,905 mm)
Length:
 ​
 • Over couplers 51 ft 3 5⁄8 in (15,637 mm)
Height ♠ 12 ft 10 in (3,912 mm)
♥ 12 ft 10 3⁄8 in (3,921 mm)
Frame type Plate
Axle load ♠ 11 LT 18 cwt (12,090 kg)
♥ 13 LT 8 cwt (13,620 kg)
 • Leading ♠ 11 LT 7 cwt (11,530 kg)
♥ 10 LT 17 cwt 2 qtr (11,050 kg)
 • Coupled ♥ 13 LT 8 cwt (13,620 kg)
 • 1st coupled ♠ 11 LT 5 cwt (11,430 kg)
 • 2nd coupled ♠ 11 LT 18 cwt (12,090 kg)
 • 3rd coupled ♠ 11 LT 5 cwt (11,430 kg)
 • Tender axle 10 LT 8 cwt (10,570 kg) average
Adhesive weight ♠ 34 LT 8 cwt (34,950 kg)
♥ 40 LT 4 cwt (40,850 kg)
Loco weight ♠ 45 LT 15 cwt (46,480 kg)
♥ 51 LT 1 cwt 2 qtr (51,890 kg)
Tender weight 31 LT 4 cwt (31,700 kg)
Total weight ♠ 76 LT 19 cwt (78,180 kg)
♥ 82 LT 5 cwt 2 qtr (83,600 kg)
Tender type YC (3-axle)
YB, YC, YE, YE1 permitted
Fuel type Coal
Fuel capacity 5 LT 10 cwt (5.6 t)
Water cap 2,590 imp gal (11,770 l)
Firebox type ♠ Round-top - ♥ Belpaire
 • Firegrate area ♠ 16.625 sq ft (1.5445 m2)
♥ 16.6 sq ft (1.54 m2)
Boiler:
 ​
 • Pitch ♠ 6 ft 8 in (2,032 mm)
♥ 7 ft (2,134 mm)
 • Diameter ♠ 4 ft 4 in (1,321 mm)
♥ 4 ft 9 in (1,448 mm)
 • Tube plates ♠ 11 ft 2 1⁄8 in (3,407 mm)
♥ 11 ft 2 1⁄8 in (3,407 mm)
 • Small tubes ♠ 185: 1 7⁄8 in (48 mm)
♥ 220: 2 in (51 mm)
Boiler pressure ♠ 160 psi (1,103 kPa)
♥ 180 psi (1,241 kPa)
Safety valve Ramsbottom
Heating surface ♠ 1,116 sq ft (103.7 m2)
♥ 1,398.5 sq ft (129.92 m2)
 • Tubes ♠ 1,015 sq ft (94.3 m2)
♥ 1,287.5 sq ft (119.61 m2)
 • Firebox ♠ 101 sq ft (9.4 m2)
♥ 111 sq ft (10.3 m2)
Cylinders Two
Cylinder size 17 in (432 mm) bore
26 in (660 mm) stroke
Valve gear Stephenson
Couplers Bell link-and-pin
AAR knuckle (1950s)
Performance figures
Tractive effort ♠ 16,690 lbf (74.2 kN) @ 75%
♥ 18,780 lbf (83.5 kN) @ 75%
Career
Operators Cape Government Railways
Imperial Military Railways
Benguela Railway
South African Railways
Sudan Railways
Class CGR 6th Class, SAR Class 6A
Number in class 50 CGR, 49 SAR
Numbers CGR 161-201, 371-376, 660-662
(371-376 renumbered 571-576)
IMR C501, C503, C509 & C510
Benguela 21
SAR 441-489
Delivered 1896-1897
First run 1896
Withdrawn 1973

The South African Railways Class 6A 4-6-0 of 1896 was a steam locomotive from the pre-Union era in the Cape of Good Hope.

In 1896 and 1897, the Cape Government Railways placed a second batch of fifty 6th Class 4-6-0 steam locomotives in service, forty-one on its Western System, six on its Midland System and three on its Eastern System. During the Second Boer War, four of them were transferred to the Imperial Military Railways on loan, and in 1907 one was sold to the Benguela Railway in Angola. In 1912, when the remaining forty-nine locomotives were assimilated into the South African Railways, they were renumbered and designated Class 6A.[1][2][3]

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, at the time the Chief Locomotive Superintendent of the CGR, and under the supervision of H.M. Beatty, at the time the 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]

H.M. Beatty

The fifty locomotives in this second batch of the 6th Class were built between 1895 and 1897, by Dübs and Company and Sharp, Stewart and Company, and were delivered in 1896 and 1897, numbered in the ranges from 161 to 201 for the CGR's Western System, 371 to 376 for the Midland System and 660 to 662 for the Eastern System.[1]

These locomotives differed from those of the previous order by having slightly larger boilers with an increased heating surface. They were the first to be delivered with Type YC tenders, which had the same coal capacity as the earlier Type YB tender of 1893, but with a water capacity of 2,590 imperial gallons (11,770 litres), compared to the 2,370 imperial gallons (10,800 litres) of the Type YB.[1]

Class 6 sub-classes

When the Union of South Africa was established on 31 May 1910, the three Colonial government railways (CGR, Natal Government Railways (NGR) and Central South African Railways (CSAR)) 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 required careful planning and was only implemented with effect from 1 January 1912.[2][4]

In 1912, all but one of these fifty locomotives were assimilated into the SAR, designated Class 6A and renumbered in the range from 441 to 489.[2][5][6]

The rest of the CGR's 6th Class locomotives, together with the Class 6-L1 to 6-L3 locomotives which had been inherited by the 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, 6B to 6H and 6J to 6L, the 2-6-2 locomotives became Class 6Y and the 2-6-4 locomotives became Class 6Z.[2][5][6]

Modifications

Several of the CSAR's Class 6-L1 to 6-L3 locomotives were modified by P.A Hyde, Chief Mechanical Engineer (CME) of the CSAR, by having their round top fireboxes replaced with larger boilers and 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.[3]

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 once again, but retaining the larger cabs. Once again, they retained their classifications.[3][6]

Service

South Africa

The Class 6 family 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" which 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 in Natal, and was used on all types of traffic.[1]

IMR, Angola and Sudan

One of these locomotives was sold to the Benguela Railway in Angola, while another four saw service with the IMR during the Second Boer War.[1][3]

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 four Class 6A locomotives in this group were numbers 465, 472, 475 and 479. They were sold to the Sudan Railways Corporation in 1942 and were renumbered in the range from M707 to M710, in the same order as their former SAR engine numbers.[1][3][7]

Renumberings

During their long service lives, some of the Class 6A locomotives underwent multiple renumberings. All were initially numbered into the CGR's Western, Midland and Eastern Systems rosters. The Midland System's locomotives, numbered in the range from 371 to 376, were later renumbered in the range from 571 to 576. The then vacant engine numbers in the range from 371 to 376 were later re-allocated to Class 8D locomotives. which were delivered in 1902.[1]

The four locomotives which were loaned to the IMR, were renumbered C501, C503, C509 and C510 for the duration of their service with the IMR during the Second Boer War, while the one which was sold to Angola, became the Benguela Railway's no. 21.[1]

The remaining forty-nine locomotives were eventually renumbered into the SAR's roster in 1912, and received SAR numbers in the range from 441 to 489. The table reflects all these renumberings as well as their builders and works numbers.[1][2][5]

lllustration

The main picture shows Sharp Stewart-built ex Western System Class 6 no. 182, later IMR no. C509, then SAR Class 6A no. 462, with a Belpaire firebox, at De Aar on 15 April 1978.

Round-top fireboxes

Belpaire fireboxes

References

  1. 1 2 3 4 5 6 7 8 9 10 Holland, D.F. (1971). Steam Locomotives of the South African Railways, Volume 1: 1859-1910 (1st ed.). Newton Abbott, Devon: David & Charles. pp. 45–46, 57. ISBN 978-0-7153-5382-0.
  2. 1 2 3 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, 28-30 (Reprinted in April 1987 by SATS Museum, R.3125-6/9/11-1000)
  3. 1 2 3 4 5 Paxton, Leith; Bourne, David (1985). Locomotives of the South African Railways (1st ed.). Cape Town: Struik. pp. 41–44. ISBN 0869772112.
  4. ↑ The South African Railways - Historical Survey. Editor George Hart, Publisher Bill Hart, Sponsored by Dorbyl Ltd., Published c. 1978, p. 25.
  5. 1 2 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. 1 2 3 South African Railways and Harbours Locomotive Diagram Book, 2'0" & 3'6" Gauge Steam Locomotives, 15 August 1941, as amended
  7. ↑ Class 6 to 6D sold to Sudan Railways during the WWII North African Campaign, list compiled by Austrian locomotive historian Reimar Holzinger
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