South African Class 15E 4-8-2

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South African Class 15E 4-8-2
SAR Class 15E 2878 (4-8-2).jpg
Henschel-built no. 2878 at Magaliesburg, 26 July 1992
Type and origin
♠ Robert Stephenson and Hawthorns engines
Henschel & Berliner engines
Power type Steam
Designer South African Railways
(A.G. Watson)
Builder Robert Stephenson & Hawthorns
Henschel and Son
Berliner Maschinenbau
Serial number RSH 4090–4109
Henschel 23000-23010, 23111-23115
Berliner 10585-10592
Model Class 15E
Build date 1935–1936
Total produced 44
Configuration 4-8-2 (Mountain)
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)
Wheelbase 65 ft 6 14 in (19,971 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 20 ft 5 in (6,223 mm)
 • Tender bogie 6 ft 2 in (1,880 mm)
 • Over couplers 73 ft 6 in (22,403 mm)
Height 12 ft 11 12 in (3,950 mm)
Frame type Bar
Axle load ♠ 18 LT 12 cwt (18,900 kg)
18 LT 14 cwt (19,000 kg)
 • Leading ♠ 18 LT 6 cwt (18,590 kg)
19 LT 5 cwt (19,560 kg)
 • 1st coupled ♠ 18 LT 3 cwt (18,440 kg)
17 LT 14 cwt (17,980 kg)
 • 2nd coupled ♠ 18 LT 12 cwt (18,900 kg)
18 LT 14 cwt (19,000 kg)
 • 3rd coupled ♠ 18 LT 10 cwt (18,800 kg)
18 LT 1 cwt (18,340 kg)
 • 4th coupled ♠ 18 LT 3 cwt (18,440 kg)
17 LT 14 cwt (17,980 kg)
 • Trailing ♠ 17 LT 6 cwt (17,580 kg)
16 LT 17 cwt (17,120 kg)
 • Tender bogie Bogie 1: 33 LT 18 cwt (34,440 kg)
Bogie 2: 35 LT 10 cwt (36,070 kg)
 • Tender axle 17 LT 15 cwt (18,030 kg)
Adhesive weight ♠ 73 LT 8 cwt (74,580 kg)
72 LT 3 cwt (73,310 kg)
Loco weight ♠ 109 LT (110,700 kg)
108 LT 5 cwt (110,000 kg)
Tender weight 69 LT 8 cwt (70,510 kg)
Total weight ♠ 178 LT 8 cwt (181,300 kg)
177 LT 13 cwt (180,500 kg)
Tender type JT (2-axle bogies)
JT, JV permitted
Fuel type Coal
Fuel capacity 14 LT (14.2 t)
Water cap 6,000 imp gal (27,300 l)
Firebox type Round-top
 • Firegrate area 63 sq ft (5.9 m2)
 • Model Watson Standard no. 3B
 • Type Domeless
 • Pitch 9 ft 2 12 in (2,807 mm)
 • Diameter 6 ft 2 14 in (1,886 mm)
 • Tube plates 22 ft 6 in (6,858 mm)
 • Small tubes 136: 2 12 in (64 mm)
 • Large tubes 36: 5 12 in (140 mm)
Boiler pressure 210 psi (1,448 kPa)
Safety valve Pop
Heating surface 3,400 sq ft (320 m2)
 • Tubes 3,168 sq ft (294.3 m2)
 • Arch tubes 26 sq ft (2.4 m2)
 • Firebox 206 sq ft (19.1 m2)
 • Heating area 676 sq ft (62.8 m2)
Cylinders Two
Cylinder size 24 in (610 mm) bore
28 in (711 mm) stroke
Valve gear Rotary cam
Valve type Poppet
Couplers AAR knuckle
Performance figures
Tractive effort 42,340 lbf (188.3 kN) @ 75%
Operators South African Railways
Rhodesia Railways
CF de Mocambique
Class Class 15E
Number in class 44
Numbers 2858-2901
Nicknames Bongol
Delivered 1935–1937
First run 1935
Withdrawn 1973

The South African Railways Class 15E 4-8-2 of 1935 was a steam locomotive.

Between 1935 and 1937, the South African Railways placed forty-four Class 15E steam locomotives with a 4-8-2 Mountain type wheel arrangement in service.[1][2][3]


The Class 15E 4-8-2 Mountain type mixed traffic steam locomotive was a refinement of the Classes 15C and 15CA. It was designed by A.G. Watson, Chief Mechanical Engineer (CME) of the South African Railways (SAR) from 1929 to 1936, and incorporated many of the improvements which had been developed by him, some of which were a vastly enlarged standardised boiler, a large and wide fire grate and a Watson cab.[1][2]

They were built by three manufacturers. In 1935, British locomotive builders Robert Stephenson and Hawthorns (RSH) delivered twenty locomotives, numbered in the range from 2858 to 2877. Henschel and Son of Kassel in Germany built and delivered sixteen in two batches in 1936, numbered in the range from 2878 to 2893. Also in 1936, German locomotive builders Berliner Maschinenbau built another eight locomotives which were delivered in 1937, numbered in the range from 2894 to 2901. The British-built locomotives were 15 long hundredweight (762 kg) heavier than the German-built ones.[1][2][3][4]


The Class 15D classification was never used by the Railways, possibly to have this locomotive’s class letter match that of the Class 16E which was delivered in the same year.[5][6]

A.G. Watson

Because of the free running that was achieved with the Classes 15E, 16E and 19C which all entered service in 1935 and were all equipped with rotary cam poppet valve gear, Watson decided to adopt this type of valve gear for all his future designs. Most valve gear components of the Class 15E were interchangeable with similar parts of the Class 16E. Like the other classes with poppet valve gear, the Class 15E was fast, but some trouble was initially experienced with the valve gear in the reverse position. This was corrected by modifying the reversing cams and these, as well as new forward cams, were manufactured at the Salt River shops in Cape Town.[1][2]

The Class 15E, nicknamed Bongol, was delivered with a Watson Standard no. 3B boiler and a Watson cab. In the 1930s, Watson designed a standard boiler type and a cab with an inclined front as part of his standardisation policy. New locomotives which were acquired in the Watson era and later, such as the Class 15E, were built with such boilers and cabs. The boiler pitch was 9 feet 2 12 inches (2,807 millimetres) above the top of the rail.[2][3][5][6]

Some of the locomotives that worked on sections with tunnels were equipped with smoke deflecting cowls around their chimneys.[1]

The 24 inches (610 millimetres) bore by 28 inches (711 millimetres) stroke cylinders were interchangeable with those of the Class 16E. A 4 12 inches (114 millimetres) thick cast-iron liner was fitted between the smokebox and its saddle to obtain this interchangeability. The cylinders had cast-iron liners and the steam and exhaust valve seatings were renewable. The connecting and coupling rods were fitted with floating bronze bushes and all crank pins were hollow bored. Soft grease lubrication was used for the motion, while the coupled wheel axle boxes were hard grease lubricated.[2]

The buffing gear between engine and tender consisted of a laminated spring, contained in a steel casting attached to the tender's front buffer beam. The tender was the Type JT which was first introduced in 1935 along with the Class 15E Mountain type and Class 16E Pacific type. The tender had a coal capacity of 14 long tons (14.2 tonnes), a water capacity of 6,000 imperial gallons (27,300 litres) and an axle load of 17 long tons 15 hundredweight (18,030 kilograms).[1][2]


South African Railways[edit]

Class 15E no. 2881 ID.jpg

The Class 15E was placed in service on the mainline between Cape Town and Beaufort West. Later, when the Classes 15F and 23 were placed in service, the Class 15E locomotives were relocated further north to work between Beaufort West and De Aar. During 1954-1955, upon the arrival of the Class 25 condensers and Class 25NC, they were displaced from the Cape mainline and all 44 Bongols were relocated, this time to Bloemfontein.[3][7]

In the 1960s they went to Bethlehem in the Orange Free State, from where they worked to Harrismith, Bloemfontein and Kroonstad. They were all withdrawn from regular service in 1973, except no. 2878 which was retained in running order for excursion trains.[3]

Other operators[edit]

Eleven of the Class 15E locomotives were eventually sold to neighbouring countries or into industrial service. Six of them were sold to Rhodesia Railways (RR) in 1970, where they retained their 15E classification but were renumbered by omitting the first digit of their SAR numbers. The Rhodesian locomotives did not last long in RR service, however, and were scrapped in 1973.[8]

Three locomotives were sold to Caminhos de Ferro de Mocambique (CFM) in 1972, where they were renumbered 721, 722 and 723 respectively.[8]

Two locomotives were sold to Dunn's Locomotive Works, to be employed at Durban Navigation Collieries (Durnacol) at Dannhauser in Natal.[8]

The table shows the Class 15E engine numbers, builders, years built, works numbers and post-SAR owners.[8]


The main picture shows preserved Henschel-built no. 2878 with elephant ear smoke deflectors at Magaliesburg, Transvaal, on 26 July 1992, while the following pictures illustrate some differences in appearance over the years.


  1. ^ a b c d e f Holland, D.F. (1972). Steam Locomotives of the South African Railways, Volume 2: 1910-1955 (1st ed.). Newton Abbott, Devon: David & Charles. pp. 72–73. ISBN 978-0-7153-5427-8. 
  2. ^ a b c d e f g Espitalier, T.J.; Day, W.A.J. (1946). The Locomotive in South Africa - A Brief History of Railway Development. Chapter VII - South African Railways (Continued). South African Railways and Harbours Magazine, October 1946. pp. 803-804.
  3. ^ a b c d e Paxton, Leith; Bourne, David (1985). Locomotives of the South African Railways (1st ed.). Cape Town: Struik. pp. 10–11, 62–63. ISBN 0869772112. 
  4. ^ Henschel-Lieferliste (Henschel & Son works list), compiled by Dietmar Stresow
  5. ^ a b South African Railways & Harbours/Suid Afrikaanse Spoorweë en Hawens (15 Aug 1941). Locomotive Diagram Book/Lokomotiefdiagramboek, 3'6" Gauge/Spoorwydte. SAR/SAS Mechanical Department/Werktuigkundige Dept. Drawing Office/Tekenkantoor, Pretoria. pp. VIII, 45.
  6. ^ a b South African Railways & Harbours/Suid Afrikaanse Spoorweë en Hawens (15 Aug 1941). Locomotive Diagram Book/Lokomotiefdiagramboek, 2'0" & 3'6" Gauge/Spoorwydte, Steam Locomotives/Stoomlokomotiewe. SAR/SAS Mechanical Department/Werktuigkundige Dept. Drawing Office/Tekenkantoor, Pretoria. pp. VIII, 6a-7a, 20, 45.
  7. ^ Soul of A Railway, System 5, Part 1: Bloemfontein. Caption 1. (Accessed on 1 March 2017)
  8. ^ a b c d Durrant, A E (1989). Twilight of South African Steam (1st ed.). Newton Abbott, London: David & Charles. p. 89. ISBN 0715386387.