South African Class 8 4-8-0

CGR 8th Class 4-8-0 1902 South African Classes 8 and 8W 4-8-0
CGR (Eastern System) 8th Class no. 779 SAR Class 8 no. 1088, East London, c. 1930
Type and origin ♠ Original locomotive, as built ♥ Superheated, outside admission valves ♣ Superheated, inside admission valves, Class 8W ʘ XD tender - ♦ XE1 tender - ʘ XF tender Power type Steam Designer Cape Government Railways (H.M. Beatty) Builder Neilson, Reid and Company Serial number 6111-6113, 6216-6225, 6241-6250 Model CGR 8th Class (4-8-0) Build date 1901-1902 Total produced 23
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 ʘ♦ʘ 33 1⁄2 in (851 mm) as built ʘ♦ʘ 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 ʘ♦ʘ 14 ft 7 in (4,445 mm)  • Tender bogie ʘ♦ʘ 4 ft 7 in (1,397 mm) Length: ​  • Over couplers 54 ft 2 in (16,510 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) ♥ 12 LT (12,190 kg)  • 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: ʘ 16 LT 15 cwt (17,020 kg) ʘ 20 LT 14 cwt (21,030 kg) Bogie 2: ʘ 17 LT 8 cwt (17,680 kg) ʘ 22 LT 7 cwt (22,710 kg)  • Tender axle ʘ 8 LT 14 cwt (8,840 kg) ♦ 9 LT 14 cwt 1 qtr (9,868 kg) av. ʘ 11 LT 3 cwt 2 qtr (11,350 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 ʘ 34 LT 3 cwt (34,700 kg) ♦ 36 LT 18 cwt (37,490 kg) ʘ 43 LT 1 cwt (43,740 kg) Total weight ♠ʘ 93 LT 8 cwt (94,900 kg) ♠♦ 96 LT 3 cwt (97,690 kg) ♠ʘ 102 LT 6 cwt (103,900 kg) ♥ʘ 94 LT 18 cwt (96,420 kg) ♥ʘ 103 LT 16 cwt (105,500 kg) ♣ʘ 95 LT 4 cwt (96,730 kg) ♣♦ 97 LT 19 cwt (99,520 kg) Tender type ʘ XD (2-axle bogies) ♦ XE1 (2-axle bogies) ʘ XF (2-axle bogies) XC, XC1, XD, XE, XE1, XF, XF1, XF2, XJ, XM, XM1, XM2, XM3 permitted Fuel type Coal Fuel capacity ʘ 5 LT 10 cwt (5.6 t) ♦ʘ 10 LT (10.2 t) Water cap ʘ 2,730 imp gal (12,400 l) ♦ 2,855 imp gal (13,000 l) ʘ 3,000 imp gal (13,600 l) Firebox type Round-top  • Firegrate area ♠ 21.35 sq ft (1.98 m2) ♥♣ 21 sq ft (1.95 m2) Boiler: ​  • Pitch ♠ 7 ft (2,134 mm) ♥♣ 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 ♠ 1,315 sq ft (122.2 m2) ♥♣ 1,081 sq ft (100.4 m2)  • Tubes ♠ 1,184 sq ft (110.0 m2) ♥♣ 950 sq ft (88 m2)  • Firebox 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 8 & 8W Number in class 23 Numbers CGR 358-365, 771-782, 801-803 SAR 1069-1091 Delivered 1902-1903 First run 1902 Withdrawn 1972
The leading coupled axle had flangeless wheels

The South African Railways Class 8 4-8-0 of 1902 was a steam locomotive from the pre-Union era in the Cape of Good Hope.

In 1902 and 1903, the Cape Government Railways placed 23 8th Class steam locomotives with a 4-8-0 Mastodon type wheel arrangement in service, three on the Cape Western System, eight on the Cape Midland System and twelve on the Cape Eastern System. In 1912, when they were assimilated into the South African Railways, they were renumbered, but retained their Class 8 classification.

The first 8th Class locomotives of the Cape Government Railways (CGR) were 2-8-0 Consolidation types, designed by H.M. Beatty, the Chief Locomotive Superintendent of the CGR from 1896 to 1910. They entered service in 1901 and were later to become 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 and the coupled wheelbase was shortened from 14 feet 6 inches (4,420 millimetres) to 13 feet 6 inches (4,115 millimetres).

The 23 locomotives of 1902 and 1903 were the first 8th Class locomotives of the CGR to be built with a 4-8-0 Mastodon type wheel arrangement. These locomotives were built by Neilson, Reid and Company in 1901 and 1902, and delivered in three batches in 1902 and 1903. In spite of the difference in wheel arrangement, these Mastodons and the earlier Consolidations of the CGR were all grouped together into the 8th Class.

They were conceived as mixed traffic locomotives, equally suitable for goods and passenger work. They had larger coupled wheels than the CGR 7th Class, bar frames, used saturated steam and had Stephenson valve gear. In service, it was found that the four-wheeled bogies and the 12 inches (305 millimetres) shorter fixed wheelbase made them steadier and easier riding than their 2-8-0 Consolidation predecessors.