South African Class 7B 4-8-0

IMR 7th Class 4-8-0
CSAR 7th Class 4-8-0
NGR Class L 4-8-0
Rhodesia Railways 7th Class
South African Classes 7B & 7BS 4-8-0

Class 7BS no. 1056 with 6½ ton coal capacity Type ZC tender, Voorbaai, 4 September 1997

Type and origin ♠ - Original locomotive, as built ♥ - Locomotive equipped with superheating ♣ - Reboilered CSAR no. 381, SAR no. 1058 Power type Steam Designer Cape Government Railways (H.M. Beatty) Builder Neilson, Reid and Company Serial number 5677, 5813-5837, 5904-5906 Model CGR 7th Class Build date 1900 Total produced 29

Specifications Configuration 4-8-0 (Mastodon) Driver 2nd coupled axle Gauge 3 ft 6 in (1,067 mm) Cape gauge Leading dia. 28 1⁄2 in (724 mm) Coupled dia. 42 3⁄4 in (1,086 mm) Tender wheels 33 1⁄2 in (851 mm) as built 34 in (864 mm) retyred Wheelbase 46 ft 2 in (14,072 mm)  • Engine 21 ft 3 1⁄2 in (6,490 mm)  • Leading 5 ft 3 in (1,600 mm)  • Coupled 12 ft (3,658 mm)  • Tender 16 ft 1 in (4,902 mm)  • Tender bogie 4 ft 7 in (1,397 mm) Length: ​  • Over couplers 53 ft 7 3⁄4 in (16,351 mm) Height 12 ft 10 in (3,912 mm) Frame type Plate Axle load ♠ 9 LT 1 cwt (9,195 kg) ♥ 9 LT 14 cwt (9,856 kg) ♣ 11 LT 2 cwt 2 qtr (11,300 kg)  • Leading ♠ 10 LT 14 cwt (10,870 kg) ♥ 11 LT 2 cwt (11,280 kg) ♣ 11 LT 8 cwt (11,580 kg)  • 1st coupled ♠ 9 LT (9,144 kg) ♥ 9 LT 8 cwt (9,551 kg) ♣ 9 LT 17 cwt 2 qtr (10,030 kg)  • 2nd coupled ♠ 9 LT (9,144 kg) ♥ 9 LT 14 cwt (9,856 kg) ♣ 10 LT 4 cwt 3 qtr (10,400 kg)  • 3rd coupled ♠ 9 LT 1 cwt (9,195 kg) ♥ 9 LT 10 cwt (9,652 kg) ♣ 10 LT 13 cwt (10,820 kg)  • 4th coupled ♠ 8 LT 19 cwt (9,094 kg) ♥ 9 LT 8 cwt (9,551 kg) ♣ 11 LT 2 cwt 2 qtr (11,300 kg)  • Tender axle 8 LT 10 cwt 2 qtr (8,662 kg) av. Adhesive weight ♠ 36 LT (36,580 kg) ♥ 38 LT (38,610 kg) ♣ 41 LT 16 cwt (42,470 kg) Loco weight ♠ 46 LT 14 cwt (47,450 kg) ♥ 49 LT 2 cwt (49,890 kg) ♣ 53 LT 5 cwt 3 qtr (54,140 kg) Tender weight 34 LT 2 cwt (34,650 kg) Total weight ♠ 80 LT 16 cwt (82,100 kg) ♥ 83 LT 4 cwt (84,540 kg) ♣ 87 LT 7 cwt 3 qtr (88,790 kg) Tender type ZC (2-axle bogies) ZA, ZB, ZC, ZE permitted Fuel type Coal Fuel capacity 5 LT 10 cwt (5.6 t) Water cap 2,600 imp gal (11,800 l) Firebox type Round-top  • Firegrate area ♠♥ 17.5 sq ft (1.63 m2) ♣ 17.2 sq ft (1.60 m2) Boiler: ​  • Pitch ♠ 6 ft 8 in (2,032 mm) ♥ 6 ft 10 in (2,083 mm) ♣ 7 ft (2,134 mm)  • Diameter ♠ 4 ft 4 in (1,321 mm) ♥ 4 ft 6 in (1,372 mm) ♣ 5 ft (1,524 mm)  • Tube plates ♠♥♣ 10 ft 9 in (3,277 mm)  • Small tubes ♠ 185: 1 7⁄8 in (48 mm) ♥ 100: 1 7⁄8 in (48 mm) ♣ 200: 2 in (51 mm)  • Large tubes ♥ 18: 5 1⁄2 in (140 mm) ♣ 40 Drummond: 2 1⁄2 in (64 mm) Boiler pressure ♠ 160 psi (1,103 kPa) 170 psi (1,172 kPa) ♥♣ 180 psi (1,241 kPa) Safety valve Ramsbottom Heating surface ♠ 1,078 sq ft (100.1 m2) ♥ 1,089 sq ft (101.171 m2) ♣ 1,348.2 sq ft (125.25 m2)  • Tubes ♠♥ 976 sq ft (90.7 m2) ♣ 1,226 sq ft (113.9 m2)  • Firebox ♠ 102 sq ft (9.5 m2) ♥ 113 sq ft (10.5 m2) ♣ 122.2 sq ft (11.35 m2) Superheater: ​  • Heating area ♥ 206 sq ft (19.1 m2) Cylinders Two Cylinder size ♠♣ 17 in (432 mm) bore 23 in (584 mm) stroke ♥ 17 1⁄2 in (444 mm) bore 23 in (584 mm) stroke Valve gear Stephenson Valve type ♠♣ Slide - ♥ Piston Couplers Johnston link-and-pin AAR knuckle (1930s)

Performance figures Tractive effort ♠ 18,660 lbf (83.0 kN) @ 160 psi (1,103 kPa) 19,810 lbf (88.1 kN) @ 170 psi (1,172 kPa) ♥ 22,240 lbf (98.9 kN) @ 180 psi (1,241 kPa) ♣ 20,990 lbf (93.4 kN) @ 180 psi (1,241 kPa) Factor of adh. 4.32

Career Operators Imperial Military Railways Rhodesia Railways Mashonaland Railways Beira-Mashonaland-Rhodesia Rhodesia Railways Northern Central South African Railways Natal Government Railways South African Railways Zambesi Saw Mills Class IMR, RR 7th Class NGR Class L CSAR, SAR Class 7B Number in class 29 IMR & RR 28 SAR Numbers IMR 106-130 PPR 7-9 RR 19 & 63 CSAR 373-400 NGR 327-329 SAR 949, 1032-1034, 1036-1058 Delivered 1900 First run 1900 Withdrawn 1972

The leading coupled axle had flangeless wheels

The South African Railways Class 7B 4-8-0 of 1900 was a steam locomotive from the pre-Union era in Transvaal.

In 1900, the Imperial Military Railways placed 25 Cape 7th Class 4-8-0 Mastodon type steam locomotives in service. In that same year, three Cape 7th Class locomotives which had been ordered by the Pretoria-Pietersburg Railway were also placed in service. All these locomotives were taken onto the Central South African Railways roster at the end of the Second Boer War in 1902. In 1906, three of these locomotives were sold to the Natal Government Railways.

In 1912, 26 of these 28 locomotives were assimilated into the South African Railways. They were followed in 1913 by the remaining two, which had been leased to Paulings as construction locomotives. All but one of these locomotives were renumbered and reclassified to Class 7B. In 1915, one more Cape 7th Class locomotive was obtained from the Rhodesia Railways and erroneously also designated Class 7B.

After the outbreak of the Second Boer War in 1899, control of all railways in the Cape of Good Hope and the Colony of Natal remained in the hands of their civil staff, but now working in co-operation with the invading British military. As possession was gradually obtained of the lines of the Orange Free State and the Zuid-Afrikaansche Republiek, the Oranje-Vrijstaat Gouvernement-Spoorwegen (OVGS) and the Nederlandsche-Zuid-Afrikaansche Spoorweg-Maatschappij (NZASM) were combined into the Imperial Military Railways (IMR). The military railway was in the hands of military and civilian staff who were appointed by the Director of Railways for the South African Field Forces, Lieutenant Colonel E.P.C. Girouard KCMG DSO RE.

Because of the damage caused during hostilities and the transportation demands of the British armed forces, a shortage of locomotives developed. In 1900, the IMR placed an order with Neilson, Reid and Company for 25 Cape 7th Class locomotives which were numbered in the range from 106 to 130 upon delivery.