South African Class MJ1 2-6-6-0

South African Class MJ1 2-6-6-0

300px 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 axle 3rd & 6th coupled axles Gauge 3 ft 6 in (1,067 mm) Cape gauge Leading dia Coupled dia as built retyred Tender wheels 34 in (864 mm) Wheelbase  • 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 Height ♠♥ Frame type Bar Axle load ♠  • Leading ♠  • 1st coupled ♠  • 2nd coupled ♠  • 3rd coupled ♠  • 4th coupled ♠  • 5th coupled ♠  • 6th coupled ♠  • Tender axle av. Adhesive weight ♠ Loco weight ♠ w/o Tender weight w/o Loco & tender weight ♠ w/o Tender type LP (2-axle bogies) Fuel type Coal Fuel capacity 10 LT (10.2 t) Water cap Boiler:  • Pitch ♠♥  • Diameter ♠ ♥  • Tube plates ♠ ♥  • Small tubes ♠ 146: 2 in (51 mm) ♥ 151: 2 in (51 mm)  • large tubes ♠ 22: ♥ 18:  • Firebox type Belpaire Boiler pressure ♠♥ 200 psi (1,379 kPa) Safety valve Ramsbottom Firegrate area ♠♥ 40 sq ft (3.7 m2) 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 ♠♥ Schmidt  • Heating area ♠ 413 sq ft (38.4 m2) ♥ 350 sq ft (33 m2) Cylinders Four High-pressure cylinder size bore 24 in (610 mm) stroke Low-pressure cylinder size 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Operators South African Railways Class Class MJ1 Number in class 8 Numbers 1666-1673 Delivered 1918 First run 1918 Withdrawn c. 1960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.

Manufacturer

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.

Characteristics

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.

During 1922, the coupled wheels were retyred and their diameter was increased from to .

Reboilering

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.

Service

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.

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.

Illustration

• Class MJ1 no. 1668.jpg

  No. 1668 at Butterworth, Eastern Cape, c. 1950