South African Class 8Z 2-8-0

The South African Railways Class 8Z 2-8-0 of 1904 was a steam locomotive from the pre-Union era in the Cape of Good Hope.

This article is about one of several different Cape Government Railways locomotive types to be designated "8th Class". For the others, see Cape Government Railways 8th Class locomotives.

CGR 8th Class 2-8-0 1904 South African Class 8Z 2-8-0
CGR 8th Class no. 825, SAR Class 8Z no. 904
Type and origin Power type Steam Designer Cape Government Railways (H.M. Beatty) Builder North British Locomotive Company Serial number 16095-16102 Model CGR 8th Class (2-8-0) Build date 1904 Total produced 8
Specifications Configuration: ​  • Whyte 2-8-0 (Consolidation)  • UIC 1'Dn2 Driver 3rd coupled axle Gauge 3 ft 6 in (1,067 mm) Cape gauge Leading dia. 28 ^1⁄2 in (724 mm) Coupled dia. 48 in (1,219 mm) Tender wheels 33 ^1⁄2 in (851 mm) as built 34 in (864 mm) retyred Wheelbase 47 ft (14,326 mm)  • Engine 21 ft 8 in (6,604 mm)  • Coupled 14 ft 6 in (4,420 mm)  • Tender 14 ft 7 in (4,445 mm)  • Tender bogie 4 ft 7 in (1,397 mm) Wheel spacing (Asymmetrical) 1-2: 4 ft 7 in (1,397 mm) 2-3: 4 ft 3 in (1,295 mm) 3-4: 5 ft 8 in (1,727 mm) Length: ​  • Over couplers 54 ft 9 ^1⁄2 in (16,700 mm) Height 12 ft 10 in (3,912 mm) Frame type Bar Axle load 13 LT (13,210 kg)  • Leading 5 LT (5,080 kg)  • 1st coupled 12 LT 11 cwt (12,750 kg)  • 2nd coupled 12 LT 17 cwt (13,060 kg)  • 3rd coupled 13 LT (13,210 kg)  • 4th coupled 13 LT (13,210 kg)  • Tender bogie Bogie 1: 17 LT 13 cwt (17,930 kg) Bogie 2: 18 LT 16 cwt (19,100 kg)  • Tender axle 9 LT 8 cwt (9,551 kg) Adhesive weight 51 LT 8 cwt (52,220 kg) Loco weight 56 LT 8 cwt (57,310 kg) Tender weight 36 LT 9 cwt (37,030 kg) Total weight 92 LT 17 cwt (94,340 kg) Tender type XE1 (2-axle bogies) Fuel type Coal Fuel capacity 10 LT (10.2 t) Water cap 2,855 imp gal (13,000 l) Firebox type Round-top  • Firegrate area 32 sq ft (3.0 m^2) Boiler: ​  • Pitch 7 ft 3 in (2,210 mm)  • Diameter 4 ft 11 in (1,499 mm)  • Tube plates 12 ft 5 ^11⁄16 in (3,802 mm)  • Small tubes 194: 2 in (51 mm) Boiler pressure 180 psi (1,241 kPa) Safety valve Ramsbottom Heating surface 1,461 sq ft (135.7 m^2)  • Tubes 1,355 sq ft (125.9 m^2)  • Firebox 106 sq ft (9.8 m^2) Cylinders Two Cylinder size 18 ^1⁄2 in (470 mm) bore 24 in (610 mm) stroke Valve gear Stephenson Valve type Slide Couplers Johnston link-and-pin
Performance figures Tractive effort 23,110 lbf (102.8 kN) @ 75%
Career Operators Cape Government Railways South African Railways Class CGR 8th Class (2-8-0) SAR Class 8Z Number in class 8 Numbers CGR 821-828, SAR 900-907 Delivered 1904 First run 1904 Withdrawn 1935
The 2nd & 3rd coupled axles had flangeless wheels

In 1904, the Cape Government Railways placed its last eight 8th Class 2-8-0 Consolidation type steam locomotives in service. Most of its other 8th Class locomotives were built with a 4-8-0 Mastodon type wheel arrangement. In 1912, when they were assimilated into the South African Railways, these eight were renumbered and designated Class 8Z.[1][2]

Manufacturer

H.M. Beatty

The first locomotive in the Cape Government Railways (CGR) 2-8-0 Consolidation type 8th Class, later to become the South African Railways (SAR) Class 8X, was designed by H.M. Beatty, the CGR's Chief Locomotive Superintendent from 1896 to 1910.[1]

In 1904, a third batch of eight of these locomotives was delivered from the North British Locomotive Company of Glasgow, Scotland. All eight were allocated to the Western System of the CGR, numbered in the range from 821 to 828.[1][3]

Characteristics

These locomotives were very similar to the previous four Kitson-built Consolidations, but slightly larger in boiler and firegrate area dimensions. They also used saturated steam and cylinders with overhead slide valves, actuated by inside Stephenson valve gear. Of the three models of Type XE1 tender which were in use at the time, these locomotives were equipped with the version which had the 10 long tons (10.2 tonnes) coal capacity.[1][2][4]

Class 8 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. Even though 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]

In 1912, these locomotives were designated Class 8Z on the South African Railways (SAR) and renumbered in the range from 900 to 907.[1][2][4]

In spite of the difference in wheel arrangement, the CGR grouped its 2-8-0 Consolidation and post-7th Class 4-8-0 Mastodon locomotives together as the 8th Class. In 1912, all these 2-8-0 and 4-8-0 locomotives, together with the Classes 8-L1 to 8-L3 4-8-0 Mastodon locomotives from the Central South African Railways (CSAR), were grouped into ten different sub-classes by the SAR. The 4-8-0 locomotives became SAR Classes 8 and 8A to 8F and the 2-8-0 locomotives became Classes 8X to 8Z.[1][4][6]

Service

In SAR service, the Class 8Z was used mainly in the Western Cape, shedded at Touws River. A few later ended up at Bloemfontein in the Orange Free State and Klerksdorp in Transvaal. They were withdrawn by 1935.[4]

Illustration

The main picture shows no. 804 at Touws River, c. 1930.

• 
  Class 8Z as depicted on a SAR museum playing card

References

1. Holland, D.F. (1971). Steam Locomotives of the South African Railways. 1: 1859–1910 (1st ed.). Newton Abbott, Devon: David & Charles. pp. 64–66. ISBN 978-0-7153-5382-0.
2. Classification of S.A.R. Engines with Renumbering Lists, issued by the Chief Mechanical Engineer's Office, Pretoria, January 1912, pp. 9, 12, 15, 36 (Reprinted in April 1987 by SATS Museum, R.3125-6/9/11-1000)
3. North British Locomotive Company works list, compiled by Austrian locomotive historian Bernhard Schmeiser
4. Paxton, Leith; Bourne, David (1985). Locomotives of the South African Railways (1st ed.). Cape Town: Struik. p. 50. 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