South African Class MJ1 2-6-6-0

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South African Class MJ1 2-6-6-0
SAR Class MJ1 1673 (2-6-6-0).jpg
SAR Class MJ1 no. 1673, c. 1920
Type and origin
♠ Locomotive as built - Reboilered locomotive
Power type Steam
Designer South African Railways
Montreal Locomotive Works
Builder Montreal Locomotive Works
Serial number 58427-58434
Model SAR Class MJ1
Build date 1918
Total produced 8
Specifications
Configuration 2-6-6-0 (Denver)
Driver 3rd & 6th coupled axles
Gauge 3 ft 6 in (1,067 mm) Cape gauge
Leading dia. 28 12 in (724 mm)
Coupled dia. 42 12 in (1,080 mm) as built
42 34 in (1,086 mm) retyred
Tender wheels 34 in (864 mm)
Wheelbase 60 ft 8 14 in (18,498 mm)
 • Engine 32 ft 8 in (9,957 mm)
 • Coupled 8 ft 4 in (2,540 mm) per unit
 • Tender 17 ft 11 in (5,461 mm)
 • Tender bogie 4 ft 7 in (1,397 mm)
Length:
 • Over couplers 68 ft 7 18 in (20,907 mm)
Height 12 ft 6 18 in (3,813 mm)
Frame type Bar
Axle load ♠ 14 LT 2 cwt (14,330 kg)
 • Leading ♠ 7 LT 10 cwt (7,620 kg)
 • 1st coupled ♠ 13 LT 13 cwt (13,870 kg)
 • 2nd coupled ♠ 13 LT 15 cwt (13,970 kg)
 • 3rd coupled ♠ 14 LT 2 cwt (14,330 kg)
 • 4th coupled ♠ 12 LT 11 cwt (12,750 kg)
 • 5th coupled ♠ 13 LT 12 cwt (13,820 kg)
 • 6th coupled ♠ 13 LT 7 cwt (13,560 kg)
 • Tender axle 12 LT 14 cwt 2 qtr (12,930 kg) av.
Adhesive weight ♠ 81 LT (82,300 kg)
Loco weight ♠ 88 LT 10 cwt (89,920 kg) w/o
Tender weight 50 LT 18 cwt (51,720 kg) w/o
Total weight ♠ 139 LT 8 cwt (141,600 kg) w/o
Tender type LP (2-axle bogies)
Fuel type Coal
Fuel capacity 10 LT (10.2 t)
Water cap 4,250 imp gal (19,300 l)
Firebox type Belpaire
 • Firegrate area 40 sq ft (3.7 m2)
Boiler:
 • Pitch 7 ft 9 18 in (2,365 mm)
 • Diameter ♠ 5 ft 2 34 in (1,594 mm)
5 ft 1 12 in (1,562 mm)
 • Tube plates ♠ 17 ft 38 in (5,191 mm)
17 ft 14 in (5,188 mm)
 • Small tubes 146: 2 in (51 mm)
151: 2 in (51 mm)
 • Large tubes 22: 5 38 in (137 mm)
18: 5 12 in (140 mm)
Boiler pressure 200 psi (1,379 kPa)
Safety valve Ramsbottom
Heating surface ♠ 2,042 sq ft (189.7 m2)
1,913 sq ft (177.7 m2)
 • Tubes ♠ 1,906 sq ft (177.1 m2)
1,780 sq ft (165 m2)
 • Firebox ♠ 136 sq ft (12.6 m2)
133 sq ft (12.4 m2)
Superheater:
 • Type Schmidt
 • Heating area ♠ 413 sq ft (38.4 m2)
350 sq ft (33 m2)
Cylinders Four
High-pressure cylinder 16 12 in (419 mm) bore
24 in (610 mm) stroke
Low-pressure cylinder 26 in (660 mm) bore
24 in (610 mm) stroke
Valve gear Walschaerts
Valve type Piston
Couplers Bell link-and-pin
AAR knuckle (1950s)
Performance figures
Tractive effort ♠ 38,170 lbf (169.8 kN) @ 50%
37,950 lbf (168.8 kN) @ 50%
Career
Operators South African Railways
Class Class MJ1
Number in class 8
Numbers 1666-1673
Delivered 1918
First run 1918
Withdrawn c. 1960

The South African Railways Class MJ1 2-6-6-0 of 1918 was a steam locomotive.

In 1918, the South African Railways placed eight Class MJ1 Mallet articulated compound steam locomotives with a 2-6-6-0 wheel arrangement in branchline service.[1][2][3][4]

Manufacturer[edit]

Because of the difficulties experienced by the usual British and German suppliers to build new locomotives during the First World War, orders for the Class MJ1 2-6-6-0 Mallet articulated compound steam locomotive were placed with Montreal Locomotive Works (MLW) in Canada. The locomotive was designed by MLW, based on the specifications for the Class MJ Mallet which was designed by D.A. Hendrie, the Chief Mechanical Engineer (CME) of the South African Railways (SAR) from 1910 to 1922. Eight of these branchline locomotives were built and delivered by MLW in November 1918, numbered in the range from 1666 to 1673.[1][2][4]

Characteristics[edit]

The locomotives were superheated, had Walschaerts valve gear and, like the Class MJ Mallets, had Belpaire fireboxes, but slightly larger boilers. When compared to the Class MJ, a distinguishing feature of the Class MJ1 was the sandbox, which was mounted on top of the boiler in North American style, to the rear of the steam dome. In general appearance, they bore a family resemblance to the Class 14C and Class 15B 4-8-2 locomotives, which were also built by MLW in 1918.[1][2][4]

During 1922, the coupled wheels were retyred and their diameter was increased from 42 12 inches (1,080 millimetres) to 42 34 inches (1,086 millimetres).[2]

Reboilering[edit]

During 1939, while W.A.J. Day was the CME of the SAR, the Classes MJ and MJ1 were modified slightly, to be reboilered with the same standard boiler.[2]

Service[edit]

The Class MJ1 was the last Mallet locomotive class to be placed in service by the SAR. All its subsequent new articulated locomotives were to be Modified Fairlies, Garratts and Union Garratts.[5]

The Class MJ1 was also intended for branchline working and joined the Class MJ Mallets in service in the Eastern Cape. All eight were still in service by March 1948, but they were all withdrawn from service by 1960.[1][4][5]

Illustration[edit]

References[edit]

  1. ^ a b c d Holland, D.F. (1972). Steam Locomotives of the South African Railways, Volume 2: 1910-1955 (1st ed.). Newton Abbott, Devon: David & Charles. pp. 36–37. ISBN 978-0-7153-5427-8. 
  2. ^ a b c d e Espitalier, T.J.; Day, W.A.J. (1945). The Locomotive in South Africa - A Brief History of Railway Development. Chapter VII - South African Railways (Continued). South African Railways and Harbours Magazine, May 1945. p. 350.
  3. ^ South African Railways and Harbours Locomotive Diagram Book, 2’0” & 3’6” Gauge Steam Locomotives, 15 August 1941, as amended
  4. ^ a b c d Paxton, Leith; Bourne, David (1985). Locomotives of the South African Railways (1st ed.). Cape Town: Struik. p. 88. ISBN 0869772112. 
  5. ^ a b Durrant, A E (1989). Twilight of South African Steam (1st ed.). Newton Abbott, London: David & Charles. pp. 24–25. ISBN 0715386387.