South African Class 6Y 2-6-2

South African Class 6Y 2-6-2
ex CGR 6th Class 2-6-2

Ex CGR 6th Class 2-6-2, SAR Class 6Y, circa 1930
Type and origin
Power type Steam
Designer Cape Government Railways
Builder Kitson and Company
Serial number 4191-4192
Model CGR 6th Class 2-6-2
Build date 1903 [1]
Total produced 2
Specifications
Configuration 2-6-2 "Prairie"
Gauge 3 ft 6 in (1,067 mm) Cape gauge
Leading wheel
diameter		 28.5 in (724 mm)
Driver diameter 60 in (1,520 mm)
Trailing wheel
diameter		 33 in (838 mm)
Wheelbase Total: 46 ft 7.625 in (14.214 m)
Engine:
10 ft 10 in (3.302 m) coupled
25 ft 9 in (7.849 m) total
Tender:
10 ft (3.048 m)
Length 56 ft 5.75 in (17.215 m)
Height 12 ft 10 in (3.912 m)
Frame Bar frame
Axle load 14.15 long tons (14.4 t) on 3rd driver
Weight on drivers 39.05 long tons (39.7 t)
Locomotive weight 56.6 long tons (57.5 t)
Tender weight 33,164 lb (15.0 t) empty
32 long tons (32.5 t) w/o
Locomotive and tender
combined weight		 89.45 long tons (90.9 t)
Tender type YE
* 3 axle tender
* 37 in (940 mm) wheels
* Length 21 ft 4.375 in (6.512 m)
Fuel type Coal
Fuel capacity 5.5 long tons (5.6 t)
Water capacity 2,825 imp gal (12,840 l)
Boiler 4 ft 7.75 in (1.416 m) inside diameter
14 ft 6.25 in (4.426 m) inside length
7 ft 0.5 in (2.146 m) pitch
Boiler pressure 180 psi (1,240 kPa)
Firegrate area 26 sq ft (2.415 m2)
Heating surface:
– Tubes		 178 tubes 2 in (50.8 mm) diameter
1,397 sq ft (129.786 m2)
– Firebox 110 sq ft (10.219 m2)
– Total 1,507 sq ft (140.005 m2)
Cylinders Two
Cylinder size 18.5 in (470 mm) bore
26 in (660 mm) stroke
Valve gear Stephenson
Performance figures
Tractive effort 20,030 lbf (89.1 kN) at 75% pressure
Career
Operator(s) Cape Government Railways
South African Railways
Class CGR 6th Class 2-6-2
SAR Class 6Y
Number in class 2
Number(s) CGR 901-902
SAR 711-712 [1][2][3]
Delivered 1903
First run 1903
Withdrawn 1934

The South African Class 6Y 2-6-2 of 1903 is a South African steam locomotive from the pre-Union era in the Cape Colony.

In 1903 the Cape Government Railways placed two 6th Class steam locomotives with a 2-6-2 Prairie type wheel arrangement in service. In 1912, when these locomotives were assimilated into the South African Railways, they were renumbered and reclassified to Class 6Y.[1][2][4]

Manufacturer

The Cape 6th Class 2-6-2 Prairie type locomotive was designed at the Salt River works of the Cape Government Railways (CGR) and was a further development of the 6th Class 2-6-4 Adriatic type. The 2-6-4 locomotive itself came about as an experimental development of the very successful 6th Class 4-6-0 locomotive and was initially also built with a 2-6-2 Prairie wheel arrangement, but eventually modified to a 2-6-4 wheel arrangement.[1]

Development

Good though the 6th Class 4-6-0 locomotives were, the requirement grew for larger and more powerful locomotives. It was becoming increasingly apparent at the time that such locomotives would require fireboxes with larger grate areas, which was not possible with the existing type of frame.[1]

To overcome this problem, CGR Chief Locomotive Superintendent H.M. Beatty prepared designs for a new locomotive with a 2-6-2 Prairie wheel arrangement, in which the frame terminated in front of the firebox, where it connected to a casting termed the "bridle casting". This casting extended out on either side and had wider spaced frames attached to it, which allowed a wider and deeper firebox. Because of the widened frames and larger firebox, trailing carrier wheels were incorporated to take the weight of the firebox. The coupled wheels were also located further forward to accommodate the deeper firebox and as a result the leading bogie was replaced by a single axle bissel truck.[1][4]

The first four locomotives of this design, later to be designated Class 6Z by the South African Railways (SAR), were placed in service in 1901, but displayed a tendency to be unsteady at speed. The design was therefore modified to a 2-6-4 Adriatic wheel arrangement and another four locomotives incorporating this improvement were ordered in 1902, while the first four locomotives were modified accordingly.[1]

In spite of their totally different appearance and wheel arrangement, the CGR designated them as 6th Class as well, possibly because they were intended as an "Improved 6th Class".[2][3]

Redesign

With an improved design of bissel truck, these two locomotives that were ordered from Kitson and Company in 1903 were once again built with a 2-6-2 Prairie wheel arrangement. They had larger boilers as well as larger 60 inches (1,520 millimetres) driving wheels, compared to the 54 inches (1,370 millimetres) of all other 6th Class locomotives. Numbered 901 and 902 for the Western System of the CGR, these two did not display the tendency to sway at speed and therefore retained their 2-6-2 wheel arrangement.[1][2]

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.[2][5]

In 1912 these two locomotives were renumbered 711 and 712 and reclassified to Class 6Y. The rest of the CGR’s 6th Class locomotives, together with the Central South African Railways (CSAR) Classes 6-L1 to 6-L3 locomotives that had been inherited from the Oranje-Vrijstaat Gouwermentspoorwegen (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 and 6J to 6L, and the eight 2-6-4 locomotives became Class 6Z.[2][3][6]

Service

In service these two locomotives proved to be very successful, being fast, powerful, and good steamers. It was the experience gained with these two locomotives which led to the introduction of the "Karoo" Class 4-6-2 Pacific type later in 1903. They spent practically their entire working lives on the Cape mainline in the Karoo region, until they were withdrawn and scrapped in 1934.[3][4]

Sides illustrated

The main picture and the following photographs offer different side views of the Class 6Y locomotive.

See also

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 Holland, D.F. (1971). Steam Locomotives of the South African Railways, Volume 1: 1859-1910 (1st ed.). Newton Abbott, Devon: David & Charles. pp. 52–54, 56. ISBN 978-0-7153-5382-0.
  2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 Classification of S.A.R. Engines with Renumbering Lists, issued by the Chief Mechanical Engineer’s Office, Pretoria, January 1912, pp. 8, 12, 14, 34 (Reprinted in April 1987 by SATS Museum, R.3125-6/9/11-1000)
  3. ↑ 3.0 3.1 3.2 3.3 Holland, D.F. (1972). Steam Locomotives of the South African Railways, Volume 2: 1910-1955 (1st ed.). Newton Abbott, Devon: David & Charles. p. 138. ISBN 978-0-7153-5427-8.
  4. ↑ 4.0 4.1 4.2 Paxton, Leith; Bourne, David (1985). Locomotives of the South African Railways (1st ed.). Cape Town: Struik. p. 45. ISBN 0869772112.
  5. ↑ The South African Railways - Historical Survey. Editor George Hart, Publisher Bill Hart, Sponsored by Dorbyl Ltd., Published c. 1978, p. 25.
  6. ↑ South African Railways and Harbours Locomotive Diagram Book, 2’0” & 3’6” Gauge Steam Locomotives, 15 August 1941, as amended