South African Class 6L 4-6-0
![]() Ex CGR Class 6, SAR Class 6L, as built with Schmidt superheater and piston valves
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Type and origin | |
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Power type | Steam |
Designer | Cape Government Railways |
Builder | North British |
Serial number | 15889 & 15888 |
Model | CGR Class 6 |
Build date | 1904[1] |
Total produced | 2 |
Specifications | |
Configuration | 4-6-0 “Ten-wheeler” (USA) |
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) |
Trailing wheel diameter |
33.5 in (851 mm) (Tender wheels) |
Wheelbase | Engine 21 ft 2 in (6.452 m) With tender 45 ft 5.5 in (13.856 m) |
Length | 52 ft 3.25 in (15.932 m) |
Height | 12 ft 10 in (3.912 m) |
Frame | Bar frame |
Axle load | 13.45 long tons (13.67 t) on 2nd driver as built 13.15 long tons (13.36 t) on 3rd driver saturated |
Weight on drivers | 38.5 long tons (39.1 t) as built 38.15 long tons (38.76 t) saturated |
Locomotive weight | 52.35 long tons (53.19 t) as built 49.9 long tons (50.7 t) saturated |
Tender weight | 36 long tons (37 t) |
Locomotive and tender combined weight |
88.35 long tons (89.77 t) as built 85.9 long tons (87.3 t) saturated |
Fuel type | Coal |
Fuel capacity | 5.5 long tons (5.6 t) |
Water capacity | 3,200 imp gal (15,000 l) |
Boiler | 4 ft 7 in (1.397 m) int dia 11 ft 2.25 in (3.410 m) int length |
Boiler pressure | 180 psi (1,240 kPa) |
Firegrate area | 18.75 sq ft (1.742 m2) |
Heating surface: – Tubes |
As built: 158 tubes 2 in (50.8 mm) ext dia 924.87 sq ft (85.923 m2) Saturated: 176 tubes 2 in (50.8 mm) ext dia 1,030 sq ft (95.690 m2) |
– Flues | 1 large 10.75 in (273 mm) dia tube 33.75 sq ft (3.135 m2) as built |
– Firebox | 109.5 sq ft (10.173 m2) as built 109 sq ft (10.126 m2) saturated |
– Total | 1,068.12 sq ft (99.232 m2) as built 1,139 sq ft (105.817 m2) saturated |
Superheater type | Schmidt, as built |
Cylinders | Two |
Cylinder size | 18.5 in (470 mm) bore as built 17.5 in (444 mm) bore saturated 26 in (660 mm) stroke |
Valve gear | Stephenson |
Performance figures | |
Tractive effort | At 75% boiler pressure: 22,250 lbf (98.973 kN) as built 19,910 lbf (88.564 kN) saturated |
Career | |
Railroad(s) | Cape Government Railways South African Railways |
Class | CGR Class 6, SAR Class 6L |
Number in class | 2 |
Number | CGR 909-910, SAR 659-660[1][2] |
Official name | CGR Class 6, SAR Class 6L |
Delivered | 1904 |
First run | 1904 |
Withdrawn | 1934 |
Disposition | Scrapped |
In 1904 the Cape Government Railways (CGR) placed its last two Class 6 4-6-0 bar framed steam locomotives in service. In 1912, when they were assimilated into the South African Railways (SAR), later renamed Spoornet and then Transnet Freight Rail (TFR), they were renumbered and reclassified to Class 6L.[1][3]
Contents
Manufacture[edit]
The Class 6 was designed at the Salt River works of the Cape Government Railways (CGR) at the same time as the Class 7. While the Class 7 was conceived primarily as a goods locomotive, the Class 6 was intended to be its fast passenger service counterpart.[1]
The CGR placed its last order for Class 6 locomotives with the North British Locomotive Company (NBL) in 1904. The two locomotives in this order were experimental and were the first South African locomotives to have piston valves and superheaters. The pistons, with a bore of 18.5 inches (470 millimetres), were the largest yet used on the Class 6. Like other second generation Class 6 locomotives, they had high running boards without driving wheel fairings. They were numbered 909 and 910 for the Western System.[1][3][4]
Schmidt superheater[edit]
Whereas in later superheater designs the superheater elements were passed down the boiler flues, on these two engines the Schmidt superheater was of the smokebox type with the tubes arranged around the shell of the smokebox. To ensure that the superheater tubes received ample heat, a large flue of 10.75 inches (273 millimetres) diameter was installed between the firebox and the front tube plate, where it connected to the casing of the superheater. In the smokebox it was necessary to provide a clearing chute beneath the smokebox where the flue joined the casing in order to prevent it from becoming clogged with cinders. Just forward of the blast pipe, another chute was installed to clear cinders from the firebox.[1]
Modification[edit]
The arrangement was extremely complicated and did not prove a success, with the result that in 1915 the two locomotives were reboilered with boilers similar to those used by the standard Class 6, thus converting them to saturated steam locomotives. The piston-valve cylinders were also removed and replaced with smaller 17.5 inches (444 millimetres) bore slide-valve cylinders. In this form they were practically identical to the bar framed Class 6J locomotives that were built by Neilson, Reid and Company in 1902, except that they still had cylinders with a 0.5 inches (12.7 millimetres) larger bore.[1]
Class 6 sub-classes[edit]
When these locomotives were assimilated into the newly established South African Railways (SAR) in 1912, they were renumbered 659 and 660 and reclassified to Class 6L. The rest of the CGR’s Class 6 locomotives, together with Class 6 locomotives that were inherited from the Oranje-Vrijstaat Gouwermentspoorwegen (OVGS) via the Imperial Military Railways (IMR) and the Central South African Railways (CSAR), as well as the CSAR’s own Classes 6-L1 to 6-L3, were grouped into thirteen more sub-classes by the SAR, the 4-6-0 locomotives becoming SAR Classes 6, 6A to 6H, 6J and 6K, the 2-6-2 locomotives becoming Class 6Y and the 2-6-4 locomotives becoming Class 6Z.[4][2]
Service[edit]
In SAR service the two Class 6L locomotives worked on the Cape main line until they were withdrawn and scrapped in 1934.[2][3]
The Class 6 series of locomotives were introduced primarily as passenger engines, 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 was used on all types of traffic.[1]
In Cape Town they held a monopoly over the suburban services until electrification arrived in 1928, and on the Reef they also worked these services between Randfontein and Springs until the loads became too heavy for them. They were employed on branch lines all over the country, Natal excluded, and practically every big station and many smaller ones had its quota of these handy locomotives to work the local passenger, goods and shunting services.[1][3]
Like the Class 7, the Class 6 family gave good service for many years. By the time the last ones were retired in 1973, the Class 6 series had achieved a service life of eighty years, a performance that can be matched by few, if any, other locomotive classes world wide.[1]
See also[edit]
- South African Class 6 4-6-0
- South African Class 6A 4-6-0
- South African Class 6B 4-6-0
- South African Class 6C 4-6-0
- South African Class 6D 4-6-0
- South African Class 6E 4-6-0
- South African Class 6F 4-6-0
- South African Class 6G 4-6-0
- South African Class 6H 4-6-0
- South African Class 6J 4-6-0
- South African Class 6K 4-6-0
- South African Class 6Y 2-6-2
- South African Class 6Z 2-6-4
- Tender locomotive numbering and classification
- Cape Government Railways
- The 4-6-0 “Ten-wheeler”
- List of South African locomotive classes
References[edit]
- ^ a b c d e f g h i j Steam Locomotives of the South African Railways, vol 1: 1859-1910, (D.F. Holland, 1971), p54, p56, ISBN 0 7153 5382 9
- ^ a b c Steam Locomotives of the South African Railways, vol 2: 1910-1955, (D.F. Holland, 1972), p138, ISBN 0 7153 5427 2
- ^ a b c d Locomotives of the South African Railways - A Concise Guide (Leith Paxton & David Bourne, 1985), p44, ISBN 0 86977 211 2
- ^ a b South African Railways and Harbours Locomotive Diagram Book, 2’0” & 3’6” Gauge Steam Locomotives, 15 August 1941, as amended
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