South African Class 8D 4-8-0

CGR 8th Class 4-8-0 1903 South African Classes 8D & 8DW 4-8-0
CGR 8th Class no. 788, SAR Class 8D no. 1223, Bloemfontein, 22 March 1970
Type and origin ♠ Original locomotive, as built ♥ Superheated, outside admission valves ♣ Superheated, inside admission valves, Class 8DW Power type Steam Designer Cape Government Railways (H.M. Beatty) Builder Neilson, Reid and Company North British Locomotive Company Serial number NR 6284-6301, 6303-6308, 6325-6334 NBL 15833-15836 Model CGR 8th Class (4-8-0) Build date 1902-1903 Total produced 38
Specifications Configuration: ​  • Whyte 4-8-0 (Mastodon)  • UIC ♠ 2'Dn2 - ♥♣ 2'Dh2 Driver 2nd 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 46 ft 10 1⁄2 in (14,288 mm)  • Engine 23 ft 3 in (7,087 mm)  • Leading 6 ft (1,829 mm)  • Coupled 13 ft 6 in (4,115 mm)  • Tender 14 ft 7 in (4,445 mm)  • Tender bogie 4 ft 7 in (1,397 mm) Length: ​  • Over couplers 54 ft 2 1⁄4 in (16,516 mm) Height ♠ 12 ft 10 in (3,912 mm) ♥♣ 12 ft 8 in (3,861 mm) Frame type Bar Axle load ♠ 11 LT 14 cwt (11,890 kg) ♥ 12 LT (12,190 kg) ♣ 12 LT 11 cwt (12,750 kg)  • Leading ♠ 12 LT 9 cwt (12,650 kg) ♥♣ 12 LT 15 cwt (12,950 kg)  • Coupled ♠ 11 LT 14 cwt (11,890 kg) all ♥ 12 LT (12,190 kg) all  • 1st coupled ♣ 11 LT 18 cwt (12,090 kg)  • 2nd coupled ♣ 12 LT 11 cwt (12,750 kg)  • 3rd coupled ♣ 11 LT 19 cwt (12,140 kg)  • 4th coupled ♣ 11 LT 18 cwt (12,090 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 ♠ 46 LT 16 cwt (47,550 kg) ♥ 48 LT (48,770 kg) ♣ 48 LT 6 cwt (49,080 kg) Loco weight ♠ 59 LT 5 cwt (60,200 kg) ♥ 60 LT 15 cwt (61,720 kg) ♣ 61 LT 1 cwt (62,030 kg) Tender weight 36 LT 9 cwt (37,030 kg) Total weight ♠ 95 LT 14 cwt (97,240 kg) ♥ 97 LT 4 cwt (98,760 kg) ♣ 97 LT 10 cwt (99,060 kg) Tender type XE1 (2-axle bogies) XC, XC1, XD, XE, XE1, XF, XF1, XF2, XJ, XM, XM1, XM2, XM3 permitted 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 ♠ 21.35 sq ft (1.983 m2) ♥♣ 21 sq ft (2.0 m2) Boiler: ​  • Pitch ♠♥♣ 7 ft 1 in (2,159 mm)  • Diameter ♠♥♣ 5 ft (1,524 mm)  • Tube plates ♠ 11 ft 1⁄2 in (3,366 mm) ♥♣ 11 ft 3⁄8 in (3,362 mm)  • Small tubes ♠ 205: 2 in (51 mm) ♥♣ 115: 2 in (51 mm)  • Large tubes ♥♣ 18: 5 1⁄2 in (140 mm) Boiler pressure 180 psi (1,241 kPa) Safety valve Ramsbottom Heating surface ♠ 1,318 sq ft (122.4 m2) ♥♣ 1,081 sq ft (100.4 m2)  • Tubes ♠ 1,185 sq ft (110.1 m2) ♥♣ 950 sq ft (88 m2)  • Firebox ♠ 133 sq ft (12.4 m2) ♥♣ 131 sq ft (12.2 m2) Superheater: ​  • Heating area ♥♣ 214 sq ft (19.9 m2) Cylinders Two Cylinder size ♠ 18 1⁄2 in (470 mm) bore ♥ 19 in (483 mm) bore ♣ 20 in (508 mm) bore ♠♥♣ 24 in (610 mm) stroke Valve gear Stephenson Valve type ♠ Slide - ♥♣ Piston Couplers Johnston link-and-pin AAR knuckle (1930s)
Performance figures Tractive effort ♠ 23,110 lbf (102.8 kN) @ 75% ♥ 24,370 lbf (108.4 kN) @ 75% ♣ 27,000 lbf (120 kN) @ 75%
Career Operators Cape Government Railways South African Railways Class CGR 8th Class, SAR Classes 8D & 8DW Number in class 38 Numbers CGR 366-384, 399, 783-794, 807-812 SAR 1192-1229 Delivered 1903 First run 1903 Withdrawn 1972
The leading coupled axle had flangeless wheels

The South African Railways Class 8D 4-8-0 of 1903 was a steam locomotive from the pre-Union era in the Cape of Good Hope.

In 1903, when the first batch of 8th Class 4-8-0 Mastodon type locomotives had been tried and proven successful, the Cape Government Railways placed another 38 8th Class 4-8-0 steam locomotives in service, six on the Western System, twenty on the Midland System and twelve on the Eastern System. In 1912, when they were assimilated into the South African Railways, they were renumbered and designated Class 8D.

The first 8th Class locomotive of the Cape Government Railways (CGR) was a 2-8-0 Consolidation type, designed by H.M. Beatty, the Chief Locomotive Superintendent of the CGR from 1896 to 1910. It was later to be designated the South African Railways (SAR) Class 8X.

While these first Schenectady- and ALCO-built 2-8-0 locomotives were being subjected to exhaustive testing on all types of traffic and under varying conditions, some trouble was experienced with the leading two-wheeled pony truck. When designs were prepared at Salt River for a later order for more locomotives, the pony truck was replaced with a four-wheeled bogie.

These 38 locomotives were the second batch of CGR 8th Class locomotives to be built with a 4-8-0 Mastodon type wheel arrangement. In spite of the difference in wheel arrangement, the CGR's new post-7th Class Consolidations and Mastodons were all grouped together into the 8th Class.

They were ordered from Neilson, Reid and Company in 1902 and were delivered in four batches in 1903. While they were being built, Neilson, Reid amalgamated with Dübs and Company and Sharp, Stewart and Company to form the North British Locomotive Company (NBL). As a result, the last four of these locomotives were delivered as having been built by NBL at the Hyde Park shops of the former Neilson, Reid.