South African Class 6K 4-6-0

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CGR 6th Class 4-6-0 1901 Baldwin
South African Class 6K 4-6-0
SAR Class 6K (4-6-0) ex CGR.jpg
Ex CGR 6th Class, SAR Class 6K
Type and origin
Power type Steam
Designer Cape Government Railways
Baldwin Locomotive Works
Builder Baldwin Locomotive Works
Serial number 18319-18322, 18348-18353
Model CGR 6th Class
Build date 1901
Total produced 10
 • Whyte 4-6-0 (Tenwheeler)
 • UIC 2'Cn2
Driver 2nd coupled axle
Gauge 3 ft 6 in (1,067 mm) Cape gauge
Leading dia. 28 12 in (724 mm)
Coupled dia. 54 in (1,372 mm)
Tender wheels 33 in (838 mm)
Wheelbase 50 ft 1 in (15,265 mm)
 • Engine 21 ft 4 in (6,502 mm)
 • Leading 6 ft (1,829 mm)
 • Coupled 11 ft 8 in (3,556 mm)
 • Tender 13 ft 8 in (4,166 mm)
 • Tender bogie 4 ft 8 in (1,422 mm)
Wheel spacing
1-2: 5 ft (1,524 mm)
2-3: 6 ft 8 in (2,032 mm)
 • Over couplers 57 ft 6 14 in (17,532 mm)
Height 12 ft 6 in (3,810 mm)
Frame type Bar
Axle load 13 LT 13 cwt (13,870 kg)
 • Leading 9 LT (9,144 kg)
 • 1st coupled 12 LT 13 cwt (12,850 kg)
 • 2nd coupled 13 LT 13 cwt (13,870 kg)
 • 3rd coupled 12 LT 18 cwt (13,110 kg)
 • Tender bogie Bogie 1: 15 LT 4 cwt (15,440 kg)
Bogie 2: 17 LT 8 cwt (17,680 kg)
Adhesive weight 39 LT 4 cwt (39,830 kg)
Loco weight 48 LT 4 cwt (48,970 kg)
Tender weight 32 LT 12 cwt (33,120 kg)
Total weight 80 LT 16 cwt (82,100 kg)
Tender type 2-axle bogies
Fuel type Coal
Fuel capacity 5 LT (5.1 t)
Water cap 3,360 imp gal (15,300 l)
Firebox type Round-top
 • Firegrate area 19 sq ft (1.8 m2)
 • Pitch 6 ft 11 in (2,108 mm)
 • Diameter 4 ft 10 34 in (1,492 mm)
 • Tube plates 11 ft 10 58 in (3,623 mm)
 • Small tubes 182: 2 in (51 mm)
Boiler pressure 180 psi (1,241 kPa)
Safety valve Pop
Heating surface 1,308 sq ft (121.5 m2)
 • Tubes 1,195 sq ft (111.0 m2)
 • Firebox 113 sq ft (10.5 m2)
Cylinders Two
Cylinder size 17 12 in (444 mm) bore
26 in (660 mm) stroke
Valve gear Stephenson
Couplers Johnston link-and-pin
Performance figures
Tractive effort 19,910 lbf (88.6 kN) @ 75%
Operators Cape Government Railways
South African Railways
Class CGR 6th Class, SAR Class 6K
Number in class 10
Numbers CGR 301-305, 795-799
SAR 649-658
Delivered 1901
First run 1901
Withdrawn 1928
The 2nd coupled axle had flangeless wheels

The South African Railways Class 6K 4-6-0 of 1901 was a steam locomotive from the pre-Union era in the Cape of Good Hope.

In 1901, ten American-built 6th Class bar-framed steam locomotives with a 4-6-0 wheel arrangement were placed in service by the Cape Government Railways. In 1912, when they were assimilated into the South African Railways, they were renumbered and designated Class 6K.[1][2][3]


The original Cape 6th Class locomotive was designed at the Salt River works of the Cape Government Railways (CGR) at the same time as the 7th Class.[1]

Three new versions of the 6th Class locomotive entered service on the CGR in 1901, two American-built and one British-built. Of the two American-built versions, one was designed and built by Baldwin Locomotive Works to the specifications of the CGR locomotive department. These ten engines were consequently somewhat different in appearance from most previous Cape 6th Class locomotives.[1]


They were larger than any of the previous 6th Class locomotives. Like the Schenectady-built Class 6G, they had larger boilers, large cabs and 17 12 inches (444 millimetres) bore cylinders, compared to the 17 inches (432 millimetres) bore cylinders of all the British-built 6th Class locomotives. They had bar frames, stovepipe chimneys and large domes and were the only 6th Class locomotives which were not delivered with Ramsbottom safety valves, having been equipped with the Pop type.[1]

Apart from the stovepipe chimney, a visually obvious distinction was their coupled wheel counterweights, which were shaped like bent rectangles, instead of the usual curved and tapered counterweights which were used on most South African locomotives. Like other second generation 6th Class locomotives, they had higher running boards without driving wheel fairings. They were numbered in the range from 301 to 305 for the CGR’s Western System and in the range from 795 to 799 for the Eastern System.[1][4]

Class 6 sub-classes[edit]

When the Union of South Africa was established on 31 May 1910, the three Colonial government railways (CGR, Natal Government Railways 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.[2][5]

When these ten locomotives were assimilated into the South African Railways (SAR) in 1912, they were renumbered in the range from 649 to 658 and designated Class 6K.[2][6]

The rest of the CGR's 6th Class locomotives, together with the Central South African Railways (CSAR) Classes 6-L1 to 6-L3 locomotives which had been inherited 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 to 6H, 6J and 6L, the 2-6-2 locomotives became Class 6Y and the 2-6-4 locomotives became Class 6Z.[2][4][6]


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. It went on to see service in all parts of the country, except Natal, and was used on all types of traffic.[1]

In SAR service, the Class 6K locomotives worked on the East London mainline until they were withdrawn by 1928.[3]


The Class 6K engine number sequence does not correspond with its builder's works number sequence. The table lists the Class 6K works numbers, CGR engine numbers and SAR renumbering.[1][2][6]


  1. ^ a b c d e f g Holland, D.F. (1971). Steam Locomotives of the South African Railways. 1: 1859–1910 (1st ed.). Newton Abbott, Devon: David & Charles. pp. 50–52, 56. ISBN 978-0-7153-5382-0. 
  2. ^ a b c d e Classification of S.A.R. Engines with Renumbering Lists, issued by the Chief Mechanical Engineer's Office, Pretoria, January 1912, pp. 8, 12, 14, 33 (Reprinted in April 1987 by SATS Museum, R.3125-6/9/11-1000)
  3. ^ a b Paxton, Leith; Bourne, David (1985). Locomotives of the South African Railways (1st ed.). Cape Town: Struik. pp. 41–44. ISBN 0869772112. 
  4. ^ a b South African Railways and Harbours Locomotive Diagram Book, 2'0" & 3'6" Gauge Steam Locomotives, 15 August 1941, as amended
  5. ^ The South African Railways - Historical Survey. Editor George Hart, Publisher Bill Hart, Sponsored by Dorbyl Ltd., Published c. 1978, p. 25.
  6. ^ a b c Holland, D. F. (1972). Steam Locomotives of the South African Railways. 2: 1910-1955 (1st ed.). Newton Abbott, Devon: David & Charles. p. 138. ISBN 978-0-7153-5427-8.