South African Class Exp 6 4-8-0

South African Class Exp 6 4-8-0
CGR Class 10 880, circa 1906,
later SAR Class Experimental 6 1244
Power type Steam
Designer Cape Government Railways
Builder Kitson and Company
Serial number 4375[1]
Model CGR Class 10[2][3]
Build date 1906
Total produced 1
Configuration 4-8-0 "Mastodon"
Gauge 3 ft 6 in (1,067 mm) Cape gauge
Leading wheel
diameter		 28.5 in (724 mm)
Driver diameter 48 in (1,220 mm)
Wheelbase Total: 49 ft 2.5 in (14.999 m)
Engine:
6 ft (1.829 m) pilot
13 ft 6 in (4.115 m) coupled
23 ft 4 in (7.112 m) total
Tender:
4 ft 7 in (1.397 m) bogie
16 ft 1 in (4.902 m) total
Length 56 ft 6.625 in (17.237 m)
Height 12 ft 10 in (3.912 m)
Axle load 13.05 long tons (13.3 t) on 2nd driver
Weight on drivers 49.5 long tons (50.3 t)
Locomotive weight 63.2 long tons (64.2 t)
Tender weight 39.7 long tons (40.3 t)
Locomotive & tender
combined weight		 102.55 long tons (104.2 t)
Tender type 2 axle bogies
Wheels 33.5 in (851 mm) dia
Fuel type Coal
Fuel capacity 7.5 long tons (7.6 t)
Water capacity 3,000 imp gal (14,000 l)
Boiler 5 ft (1.524 m) int dia
11 ft 4 in (3.454 m) int length
7 ft 5 in (2.261 m) pitch
Boiler pressure 180 psi (1,240 kPa)
Firegrate area 31.2 sq ft (2.899 m2)
Heating surface:
Tubes		 215 tubes 2 in (50.8 mm) ext dia
1,274.6 sq ft (118.414 m2)
Heating surface:
Firebox		 123.7 sq ft (11.492 m2)
Heating surface:
Total		 1,398.3 sq ft (129.906 m2)
Cylinders Two
Cylinder size 20 in (508 mm) bore
24 in (610 mm) stroke
Valve gear Stephenson
Tractive effort 27,010 lbf (120.1 kN) at 75% boiler pressure[1]
Career Cape Government Railways
South African Railways
Class CGR Class 10
SAR Class Exp 6[2][3]
Number in class 1
Number CGR 880, SAR 1244[2][3]
Delivered 1906
First run 1906
Withdrawn 1938[4]
Disposition Retired

In 1906 the Cape Government Railways placed a single experimental Class 10 steam locomotive with a 4-8-0 Mastodon wheel arrangement in service on the Cape Eastern System. In 1912, when this locomotive was assimilated into the South African Railways, it was renumbered and classified as Class Experimental 6.[1][2][4]

Contents

Manufacturer

The Cape Class 10 steam locomotive was designed by H.M. Beatty, the Locomotive Superintendent of the Cape Government Railways (CGR) from 1896 to 1910. The designs were prepared at the Salt River shops of the CGR in Cape Town. It was in most respects a larger and more powerful version of his Cape Class 8 of 1904, later the Class 8F, and represented a further effort on Beatty’s part to improve the steaming efficiency of the Class 8. The locomotive was delivered by Kitson and Company in 1906 and was numbered 880.[1][2][4]

Characteristics

It had Stephenson valve gear and used saturated steam. With this locomotive, as with the Cape Mikado delivered by the same manufacturer earlier in that same year, Beatty overcame his aversion to boiler centre lines that exceeded twice the Cape gauge track width of 3 feet 6 inches (1.067 metres) above the railhead. The boiler pitch of the Cape Class 10 was at 7 feet 5 inches (2.261 metres).[1]

In the designs of the Cape Class 9 and the Cape Mikado, later the Classes Experimental 4 and Experimental 5, Beatty achieved improved steaming efficiency by extending the locomotive frames with bridle castings to accommodate deep and wide fireboxes. With the Class 10 he attempted to obtain a wide firebox by spreading the grate over the rear driving wheels, hence the requirement to raise the boiler centre line. The result was a firebox that was virtually a copy of the one that was used on the Hendrie B locomotive, later the Class 1, that was placed in service on the Natal Government Railways (NGR) in 1904.[1][4]

Service

The locomotive was placed in service on the Cape Eastern System, working on the main line out of East London. It proved to be very successful in service and was able to handle loads of 280 long tons (284.5 tonnes) up the steep 1 in 40 gradient of the main line that started right at the end of the departure platform at East London station at the time. This compared well to the 240 long tons (243.9 tonnes) that the Cape Class 8 could manage.[1][4]

Despite its good performance, the design was never repeated since some trouble was experienced with the firebox. Instead, Beatty decided that more powerful locomotives could be designed using the wide and deep firebox that he used in his "Karoo" type, later the Class 5A, and the Cape Class 10 therefore remained one of a kind.[1]

In 1912, when the Cape Class 10 was assimilated into the South African Railways (SAR), it was classified as Class Experimental 6 and renumbered to 1244. It was withdrawn from service in 1938.[2][4]

See also

References

  1. ^ a b c d e f g h Holland, D.F. (1971). Steam Locomotives of the South African Railways, Volume 1: 1859-1910 (1st ed.). Newton Abbott, Devon: David & Charles. p. 72. ISBN 0715353829. 
  2. ^ a b c d e f Classification of S.A.R. Engines with Renumbering Lists, issued by the Chief Mechanical Engineer’s Office, Pretoria, January 1912, pp. 9, 12, 15, 43 (Reprinted in April 1987 by SATS Museum, R.3125-6/9/11-1000)
  3. ^ a b c Holland, D.F. (1972). Steam Locomotives of the South African Railways, Volume 2: 1910-1955 (1st ed.). Newton Abbott, Devon: David & Charles. p. 140. ISBN 0715354272. 
  4. ^ a b c d e f Paxton, Leith; Bourne, David (1985). Locomotives of the South African Railways (1st ed.). Cape Town: Struik. p. 83. ISBN 0869772112.