South African Class 6Y 2-6-2

The South African Railways Class 6Y of 1903 was a steam locomotive from the pre-Union era in the Cape of Good Hope.

In 1903, the Cape Government Railways placed two 6th Class steam locomotives with a Prairie type wheel arrangement in service. In 1912, when these locomotives were assimilated into the South African Railways, they were renumbered and designated Class 6Y.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)

Manufacturer

The Cape 6th Class 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 Adriatic type. The 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 Prairie wheel arrangement, but eventually modified to a wheel arrangement.

Development

Good though the 6th Class 4-6-0 locomotives were, the requirement grew for larger and more powerful engines. 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.

To overcome this problem, CGR Chief Locomotive Superintendent H.M. Beatty prepared designs for a new locomotive with a Prairie wheel arrangement in which the frame terminated in front of the firebox, where it connected to a casting which he 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.

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. They displayed a tendency to be unsteady at speed and the design was therefore modified to a Adriatic type wheel arrangement. Another four locomotives which incorporated this improvement were ordered in 1902, while the first four locomotives were modified accordingly.

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.

Redesign

With an improved design of bissel truck, another two locomotives were ordered from Kitson and Company in 1903 and were once again built with a Prairie wheel arrangement. They had larger boilers as well as larger coupled wheels, compared to the coupled wheels of all other 6th Class locomotives. Numbered 901 and 902 for the Western System of the CGR, these two engines did not display the tendency to sway at speed and therefore retained their wheel arrangement.

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 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.''The South African Railways - Historical Survey''. Editor George Hart, Publisher Bill Hart, Sponsored by Dorbyl Ltd., Published c. 1978, p. 25.

In 1912, these two locomotives were renumbered 711 and 712 and designated Class 6Y on the SAR. The rest of the CGR's 6th Class locomotives, together with the Central South African Railways Classes 6-L1 to 6-L3 locomotives which had been inherited from the ''Oranje-Vrijstaat Gouwermentspoorwegen'' via the Imperial Military Railways, 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 locomotives became Class 6Z.South African Railways and Harbours Locomotive Diagram Book, 2'0" & 3'6" Gauge Steam Locomotives, 15 August 1941, as amended

Service

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

Illustration

File:CGR Class 6Y 2-6-2 at Three Sisters .jpg, CGR 6th Class at Three Sisters, c. 1905
File:SAR Class 6Y 711 (2-6-2).jpg, Ex CGR 6th Class no. 901, SAR Class 6Y no. 711, at Touws River, c. 1930
File:SAR Class 6Y (2-6-2).jpg, Ex CGR 6th Class 2-6-2, SAR Class 6Y, c. 1930

References

{{Steam locomotive tenders

1430
1430
2-6-2 locomotives
1C1 locomotives
Kitson locomotives
Cape gauge railway locomotives
Railway locomotives introduced in 1903
1903 in South Africa
Scrapped locomotives