South African Class 8 4-8-0

CGR 8th Class 4-8-0 1902
South African Classes 8 and 8W 4-8-0

300px 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 4-8-0 (Mastodon) Driver axle 2nd coupled axle Gauge 3 ft 6 in (1,067 mm) Cape gauge Leading dia Coupled dia 48 in (1,219 mm) Tender wheels ʘ♦ʘ as built ʘ♦ʘ 34 in (864 mm) retyred Wheelbase  • 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 ♠ ♥ ♣  • Leading ♠ ♥♣  • 1st coupled ♣  • 2nd coupled ♣  • 3rd coupled ♣  • 4th coupled ♣  • Tender bogie Bogie 1: ʘ ʘ Bogie 2: ʘ ʘ  • Tender axle ʘ ♦ av. ʘ Adhesive weight ♠ ♥ ♣ Loco weight ♠ ♥ ♣ Tender weight ʘ ♦ ʘ Loco & tender weight ♠ʘ ♠♦ ♠ʘ ♥ʘ ♥ʘ ♣ʘ ♣♦ 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 ♦ ʘ Boiler:  • Pitch ♠ 7 ft (2,134 mm) ♥♣ 7 ft 1 in (2,159 mm)  • Diameter 5 ft (1,524 mm)  • Tube plates ♠ ♥♣  • Small tubes ♠ 205: 2 in (51 mm) ♥♣ 115: 2 in (51 mm)  • large tubes ♥♣ 18:  • Firebox type Round-top Boiler pressure 180 psi (1,241 kPa) Safety valve Ramsbottom Firegrate area ♠ 21.35 sq ft (1.98 m2) ♥♣ 21 sq ft (1.95 m2) 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 ♠ bore ♥ 19 in (483 mm) bore ♣ 20 in (508 mm) bore ♠♥♣ 24 in (610 mm) stroke Valve gear Stephenson Valve type ♠ Slide - ♥♣ Piston Couplers Bell link-and-pin AAR knuckle (1950s)

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 twenty-three 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.

Manufacture

Evolution

File:H.M. Beatty.jpg

H.M. Beatty

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. It was 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 and, when designs were prepared at Salt River for a later order for more locomotives, the pony truck was replaced with a four-wheeled bogie.

Manufacturer

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 Consolidations and Mastodons 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 slightly shorter fixed wheelbase made them steadier and easier riding than their 2-8-0 Consolidation predecessors.

Tenders

The first batch of three, numbered in the range from 801 to 803, went to the CGR's Western System in 1902. They were delivered with Type XD tenders, which had a coal capacity of 5 long tons 10 hundredweight (5.6 tonnes) and a water capacity of .

Of the second batch of ten, which arrived in 1902, eight were numbered in the range from 358 to 365 and allocated to the Midland System, while the other two became numbers 771 and 772, allocated to the Eastern System. These engines were delivered with Type XE1 tenders, which had a coal capacity of 10 long tons (10.2 tonnes) and a water capacity of .

The last batch of ten, numbered in the range from 773 to 782, arrived in 1903 and all went to the Eastern System. These engines were delivered with Type XF tenders, which also had a coal capacity of 10 long tons (10.2 tonnes), but a water capacity of .

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. 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 required careful planning and was only implemented with effect from 1 January 1912.

When these 23 locomotives were assimilated into the South African Railways (SAR) in 1912, they were renumbered in the range from 1069 to 1091, but they retained their Class 8 classification.

The rest of the 8th Class Consolidations and Mastodons of the CGR, together with the Class 8-L1 to 8-L3 4-8-0 Mastodon locomotives of the Central South African Railways, were grouped into nine more different sub-classes by the SAR. The other 4-8-0 locomotives became SAR Classes 8A to 8F and the 2-8-0 locomotives became Classes 8X to 8Z.

Modification

During A.G. Watson's term as Chief Mechanical Engineer of the SAR from 1929 to 1936, many of the Class 8 to Class 8F locomotives were equipped with superheated boilers, larger bore cylinders and either inside or outside admission piston valves. The outside admission locomotives had their cylinder bore increased from to 19 inches (483 millimetres) and retained their existing SAR Class 8 classifications, while the inside admission locomotives had their cylinder bore increased to 20 inches (508 millimetres) and were reclassified by having a "W" suffix added to their existing SAR classification letters.

Of the Class 8 locomotives, five were equipped with superheated boilers, 19 inches (483 millimetres) bore cylinders and outside admission piston valves, while retaining their Class 8 classification.

Four locomotives were equipped with superheated boilers, 20 inches (508 millimetres) bore cylinders and inside admission piston valves and reclassified to Class 8W.

The Class 8 and Class 8W works numbers, renumbering and superheating modifications are shown in the table.

Neilson, Reid-built Class 8 & 8W
Works numbers, renumbering and modification

Year	Works No.	CGR No.	CGR System	SAR No.	SAR Model
1901	6111	801	Western	1069
1901	6112	802	Western	1070	Superheated
1901	6113	803	Western	1071
1902	6216	358	Midland	1072
1902	6217	359	Midland	1073	Class 8W
1902	6218	360	Midland	1074	Class 8W
1902	6219	361	Midland	1075
1902	6220	362	Midland	1076
1902	6221	363	Midland	1077	Class 8W
1902	6222	364	Midland	1078	Class 8W
1902	6223	365	Midland	1079
1902	6224	771	Eastern	1080
1902	6225	772	Eastern	1081
1902	6241	773	Eastern	1082	Superheated
1902	6242	774	Eastern	1083
1902	6243	775	Eastern	1084
1902	6244	776	Eastern	1085	Superheated
1902	6245	777	Eastern	1086	Superheated
1902	6246	778	Eastern	1087
1902	6247	779	Eastern	1088	Superheated
1902	6248	780	Eastern	1089
1902	6249	781	Eastern	1090
1902	6250	782	Eastern	1091

Service

In SAR service, the Class 8 4-8-0 family of locomotives served on every system in the country and, in the 1920s, became the mainstay of motive power on many branchlines. Their final days were spent in shunting service. By 1972, they were all withdrawn from service.

Illustration

The main picture shows Class 8 no. 1088, ex CGR no. 779, at East London c. 1930, as built with slide valves, but with a rebuilt tender. The following pictures serve to illustrate the original slide valve configuration and the modified piston valve and superheating configuration.

• 

  Ex CGR Eastern System no. 778, SAR no. 1087, as built without superheating, c. 1930

• SAR Class 8 (4-8-0).jpg

  Superheated Class 8 with outside admission piston valves at Braamfontein, c. 1930