South African Class 15F 4-8-2

South African Class 15F 4-8-2
No. 2940 Lynette at speed on the Johannesburg-Magaliesburg line, 6 April 1992
Type and origin ♠ Numbers 2902-2915 & 2917-2966 - ♥ Number 2916 ♣ Numbers 2967-3056 - ♦ Numbers 3057-3156 Power type Steam Designer South African Railways (W.A.J. Day) Builder Berliner Maschinenbau Henschel and Son North British Locomotive Company Beyer, Peacock and Company Order number BP 1554, 1555 Serial number Berliner 10820-10826 Henschel 23932-23945 NBL 24463-24506, 25536-25595, 25941-26040 BP 7082-7111 Model Class 15F Build date 1938-1947 Total produced 255
Specifications Configuration: ​  • Whyte 4-8-2 (Mountain)  • UIC 2'D1'h2 Driver 2nd coupled axle Gauge 3 ft 6 in (1,067 mm) Cape gauge Leading dia. 30 in (762 mm) Coupled dia. 60 in (1,524 mm) Trailing dia. 34 in (864 mm) Tender wheels 34 in (864 mm) all Minimum curve 275 ft (84 m) Wheelbase JT, ET: 65 ft 6 3⁄16 in (19,969 mm)  • Engine 35 ft 8 in (10,871 mm)  • Leading 6 ft 10 in (2,083 mm)  • Coupled 15 ft 9 in (4,801 mm)  • Tender JT: 20 ft 5 in (6,223 mm) JV: 24 ft 11 in (7,595 mm) ET: 20 ft 5 in (6,223 mm) EW: 30 ft 8 in (9,347 mm)  • Tender bogie JT, ET: 6 ft 2 in (1,880 mm) EW: 8 ft 8 in (2,642 mm) Length: ​  • Over couplers JT, ET: 73 ft 5 15⁄16 in (22,401 mm) Width 10 ft (3,048 mm) Height 12 ft 11 1⁄2 in (3,950 mm) Frame type Bar Axle load ♠ 18 LT 2 cwt (18,390 kg) ♥ 18 LT 8 cwt (18,700 kg) ♣ 18 LT 19 cwt (19,250 kg) ♦ 18 LT 15 cwt (19,050 kg)  • Leading ♠ 20 LT (20,320 kg) ♥ 19 LT 7 cwt (19,660 kg) ♣ 20 LT 12 cwt (20,930 kg) ♦ 20 LT 10 cwt (20,830 kg)  • 1st coupled ♠ 17 LT 15 cwt (18,030 kg) ♥ 18 LT 1 cwt (18,340 kg) ♣ 18 LT 19 cwt (19,250 kg) ♦ 18 LT 10 cwt (18,800 kg)  • 2nd coupled ♠ 18 LT 2 cwt (18,390 kg) ♥ 18 LT 8 cwt (18,700 kg) ♣ 18 LT 13 cwt (18,950 kg) ♦ 18 LT 15 cwt (19,050 kg)  • 3rd coupled ♠ 18 LT 2 cwt (18,390 kg) ♥ 18 LT 8 cwt (18,700 kg) ♣ 18 LT 13 cwt (18,950 kg) ♦ 18 LT 15 cwt (19,050 kg)  • 4th coupled ♠ 17 LT 15 cwt (18,030 kg) ♥ 18 LT 1 cwt (18,340 kg) ♣ 18 LT 9 cwt (18,750 kg) ♦ 18 LT 10 cwt (18,800 kg)  • Trailing ♠ 16 LT 18 cwt (17,170 kg) ♥ 16 LT (16,260 kg) ♣ 18 LT 5 cwt (18,540 kg) ♦ 18 LT 6 cwt (18,590 kg)  • Tender bogie Bogie 1: JT: 33 LT 18 cwt (34,440 kg) ET: 33 LT 18 cwt (34,440 kg) EW: 54 LT 14 cwt (55,580 kg) Bogie 2: JT: 35 LT 10 cwt (36,070 kg) ET: 35 LT 10 cwt (36,070 kg) EW: 54 LT (54,870 kg)  • Tender axle JT: 17 LT 15 cwt (18,030 kg) JV: 14 LT 18 cwt (15,140 kg) ET: 17 LT 15 cwt (18,030 kg) EW: 18 LT (18,290 kg) Adhesive weight ♠ 71 LT 14 cwt (72,850 kg) ♥ 72 LT 18 cwt (74,070 kg) ♣ 74 LT 14 cwt (75,900 kg) ♦ 74 LT 10 cwt (75,700 kg) Loco weight ♠ 108 LT 12 cwt (110,300 kg) ♥ 108 LT 5 cwt (110,000 kg) ♣ 113 LT 11 cwt (115,400 kg) ♦ 113 LT 6 cwt (115,100 kg) Tender weight JT: 69 LT 8 cwt (70,510 kg) JV: 78 LT (79,250 kg) ET: 69 LT 8 cwt (70,510 kg) EW: 107 LT 14 cwt (109,400 kg) Total weight ♠JT 178 LT (180,900 kg) ♥JT 177 LT 13 cwt (180,500 kg) ♠JV 186 LT 12 cwt (189,600 kg) ♥JV 186 LT 5 cwt (189,200 kg) ♣JT 182 LT 19 cwt (185,900 kg) ♦ET 182 LT 14 cwt (185,600 kg) ♦EW 221 LT (224,500 kg) Tender type ♠♥♣ JT (2-axle bogies) ♠♥♣ JV (2-8-2) ♦ ET (2-axle bogies) ♦ EW (3-axle bogies) Fuel type Coal Fuel capacity JT: 14 LT (14.2 t) JV: 15 LT (15.2 t) ET: 14 LT (14.2 t) EW: 18 LT (18.3 t) Water cap JT: 6,000 imp gal (27,300 l) JV: 7,250 imp gal (33,000 l) ET: 5,620 imp gal (25,500 l) EW: 9,200 to 9,500 imp gal (41,800 to 43,200 l) Firebox type Round-top  • Firegrate area ♠♥♦ 63 sq ft (5.9 m2) ♣ 62.5 sq ft (5.81 m2) Boiler: ​  • Model Watson Standard no. 3B  • Type Domeless  • Pitch 9 ft 2 1⁄2 in (2,807 mm)  • Diameter 6 ft 2 1⁄4 in (1,886 mm)  • Tube plates 22 ft 6 in (6,858 mm)  • Small tubes 136: 2 1⁄2 in (64 mm)  • Large tubes 36: 5 1⁄2 in (140 mm) Boiler pressure 210 psi (1,448 kPa) Safety valve Ross-pop Heating surface ♠♥♦ 3,400 sq ft (320 m2) ♣ 3,414.5 sq ft (317.22 m2)  • Tubes ♠♥♦ 3,168 sq ft (294.3 m2) ♣ 3,179 sq ft (295.3 m2)  • Arch tubes 26 sq ft (2.4 m2)  • Firebox 206 sq ft (19.1 m2) Superheater: ​  • Heating area ♠♥♦ 676 sq ft (62.8 m2) ♣ 661 sq ft (61.4 m2) Cylinders Two Cylinder size 24 in (610 mm) bore 28 in (711 mm) stroke Valve gear Walschaerts Valve type Piston Loco brake Pre-war: Steam Post-war: Vacuum Couplers AAR knuckle
Performance figures Tractive effort 42,340 lbf (188.3 kN) @ 75% Factor of adh. 3•86
Career Operators South African Railways Class Class 15F Number in class 255 Numbers 2902–3156 Delivered 1938-1948 First run 1938 Withdrawn 1980s

External video

South African Steam: 15F 3153 Magaliesburg Express 1994 Class 15F no. 3153 at Magaliesburg and during the return trip to Johannesburg in July 1994. (Time 6:17)

External video

Class 15F no. 2916, Malmesbury to Moravia (16 June 2002) Class 15F no. 2916 at work between Malmesbury and De Hoek in the Swartland, on the Steam Loco Safari Tours trip in 2002. (Time 13:20)

External video

Class 15F nos. 2916 and 3153, Malmesbury (17 June 2002) Steam Loco Safari Tours trip in 2002. Class 15F nos. 2916 and 3153 double heading from Malmesbury southwards on the following day. (Time 13:49)

The South African Railways Class 15F 4-8-2 of 1938 was a steam locomotive.

The Class 15F was the most numerous steam locomotive class in South African Railways service. Between 1938 and 1948, 255 of these locomotives with a 4-8-2 Mountain type wheel arrangement entered service.

The Class 15F 4-8-2 Mountain type steam locomotive was designed by W.A.J. Day, Chief Mechanical Engineer (CME) of the South African Railways (SAR) from 1936 to 1939, based on the design of the Class 15E by his predecessor, A.G. Watson, and later modified again by his successor, M.M. Loubser. It was built in five batches by four locomotive manufacturers in Germany and the United Kingdom over a period of ten years spanning the Second World War.

The Class 15F represented the ultimate stage in a long history of development spanning thirty years. The first Class 15 4-8-2 tender loco­motive entered SAR service in 1914. It sported a 40 square feet (3.7 square metres) grate, a boiler pressure of 185 pounds per square inch (1,276 kilopascals), a maximum axle load of 16 long tons 10 hundredweight (16,760 kilograms) and 57 inches (1,448 millimetres) diameter coupled wheels. Later models incorporated major improvements in succession, until the Class 15CA was commissioned in 1926 with a 48 square feet (4.5 square metres) grate, a boiler pressure of 210 pounds per square inch (1,448 kilopascals), a maximum axle load of 17 long tons 15 hundredweight (18,030 kilograms) and 60 inches (1,524 millimetres) diameter coupled wheels.

The Class 15F locomotive was similar to its predecessor Class 15E, but it was built with Walschaerts valve gear as specified by Day, who was not a protagonist of rotary cam poppet valve gear. This and some other differences led to these engines being designated Class 15F. The locomotives used Stone's electric lighting, with a 150 watt Tonum E type headlight, cab lighting which included a light over the reversing controls, a bunker light and rear headlights on the tender. The locomotive was capable of traversing curves of 275 feet (84 metres) radius with ³⁄₄ inch (19 millimetres) gauge widening.