South African Class Experimental 5 2-8-2

CGR 9th Class 2-8-2 1906 South African Class Experimental 5 2-8-2
CGR 9th Class no. 840, c. 1906
Type and origin Power type Steam Designer Cape Government Railways (H.M. Beatty) Builder Kitson and Company Serial number 4341 Model CGR 9th Class Build date 1906 Total produced 1
Specifications Configuration: ​  • Whyte 2-8-2 (Mikado)  • UIC 1'D1'n2 Driver 3rd coupled axle Gauge 3 ft 6 in (1,067 mm) Cape gauge Leading dia. 28 1⁄2 in (724 mm) Coupled dia. 54 in (1,372 mm) Trailing dia. 33 in (838 mm) Tender wheels 33 1⁄2 in (851 mm) as built 34 in (864 mm) retyred Wheelbase 55 ft 1 1⁄4 in (16,796 mm)  • Engine 29 ft 9 in (9,068 mm)  • Coupled 14 ft 7 in (4,445 mm)  • Tender 16 ft 1 in (4,902 mm)  • Tender bogie 4 ft 7 in (1,397 mm) Wheel spacing (Asymmetrical) 1-2: 5 ft 1 in (1,549 mm) 2-3: 4 ft 8 in (1,422 mm) 3-4: 4 ft 10 in (1,473 mm) Length: ​  • Over couplers 63 ft 3⁄8 in (19,212 mm) Height 12 ft 10 in (3,912 mm) Frame type Bar Axle load 14 LT 3 cwt (14,380 kg)  • Leading 6 LT 10 cwt 2 qtr (6,630 kg)  • 1st coupled 14 LT 3 cwt (14,380 kg)  • 2nd coupled 13 LT 2 cwt (13,310 kg)  • 3rd coupled 13 LT 13 cwt (13,870 kg)  • 4th coupled 13 LT 17 cwt (14,070 kg)  • Trailing 11 LT 1 cwt (11,230 kg)  • Tender bogie Bogie 1: 19 LT 2 cwt (19,410 kg) Bogie 2: 20 LT 12 cwt (20,930 kg)  • Tender axle 9 LT 11 cwt (9,703 kg) Adhesive weight 54 LT 15 cwt (55,630 kg) Loco weight 72 LT 6 cwt 2 qtr (73,490 kg) Tender weight 39 LT 14 cwt (40,340 kg) Total weight 112 LT 0 cwt 2 qtr (113,800 kg) Tender type XF2 (2-axle bogies) Fuel type Coal Fuel capacity 7 LT 10 cwt (7.6 t) Water cap 3,000 imp gal (13,600 l) Firebox type Round-top  • Firegrate area 33.1 sq ft (3.08 m2) Boiler: ​  • Pitch 7 ft 3 in (2,210 mm)  • Diameter 5 ft 6 3⁄8 in (1,686 mm)  • Tube plates 17 ft (5,182 mm)  • Small tubes 203: 2 1⁄4 in (57 mm) Boiler pressure 180 psi (1,241 kPa) Safety valve Ramsbottom Heating surface 2,162.5 sq ft (200.90 m2)  • Tubes 2,032.8 sq ft (188.85 m2)  • Firebox 129.7 sq ft (12.05 m2) Cylinders Two Cylinder size 20 in (508 mm) bore 28 in (711 mm) stroke Valve gear Stephenson Couplers Johnston link-and-pin
Performance figures Tractive effort 28,000 lbf (120 kN) @ 75%
Career Operators Cape Government Railways South African Railways Class CGR 9th Class Mikado SAR Class Experimental 5 Number in class 1 Numbers CGR 840, SAR 948 Delivered 1906 First run 1906 Withdrawn 1929
The 2nd & 3rd coupled axles had flangeless wheels

The South African Railways Class Experimental 5 2-8-2 of 1906 was a steam locomotive from the pre-Union era in the Cape of Good Hope.

In 1906, the Cape Government Railways placed a single experimental 9th Class steam locomotive with a 2-8-2 Mikado type wheel arrangement in service. In 1912, when this locomotive was assimilated into the South African Railways, it was renumbered and designated Class Experimental 5. The design was never repeated.

The Cape 9th Class Mikado type steam locomotive was designed by H.M. Beatty, the Locomotive Superintendent of the Cape Government Railways (CGR) from 1896 to 1910. It was a larger version of his 9th Class of 1903, which was also built with a bar frame and Stephenson’s Link valve gear and which also used saturated steam. The locomotive was delivered with a Type XF2 tender by Kitson and Company in 1906 and was numbered 840.

At the time, the locomotive was considered as a big advance in motive power. It was a large engine and on the CGR it was exceeded in size only by the experimental Kitson-Meyer 0-6-0+0-6-0 locomotive which had entered service in 1903.

With this locomotive, Beatty overcame his aversion to boiler centre lines which exceeded twice the Cape gauge width of 3 feet 6 inches (1,067 millimetres) above the railhead, by raising the boiler pitch to 7 feet 3 inches (2,210 millimetres). The locomotive was larger than its predecessor 9th Class of 1903 in all respects, with a longer boiler which had a bigger girth, larger diameter pistons with a longer stroke, larger diameter driving wheels, a larger firebox, and a tender with a larger fuel and water capacity. The design was, however, never repeated and the Cape 9th Class Mikado remained unique.

The locomotive was placed in service on the Western System, working on the mainline between Touws River and Prince Albert Road in the Karoo. When it was determined by the Civil Department of the CGR that the engine was too heavy for the rails and bridges on this section, it was transferred to the section between Beaufort West and De Aar where heavier rail was in use.