South African Class KM 0-6-0+0-6-0

CSAR Class M 0-6-0+0-6-0
South African Class KM 0-6-0+0-6-0

SAR Class KM no. 1600, ex CSAR Class M no. 1000, c. 1915 in Johannesburg station

Type and origin Power type Steam Designer Kitson and Company Builder Kitson and Company Serial number 4262 Model CSAR Class M Build date 1904 Total produced 4

Specifications Configuration 0-6-0+0-6-0 (Kitson-Meyer) Driver 1st & 4th coupled axles Gauge 3 ft 6 in (1,067 mm) Cape gauge Coupled dia. 48 in (1,219 mm) Tender wheels 33 1⁄2 in (851 mm) Wheelbase 58 ft 4 1⁄2 in (17,793 mm)  • Engine 34 ft (10,363 mm)  • Coupled 8 ft 6 in (2,591 mm) each  • Tender 14 ft 7 in (4,445 mm)  • Tender bogie 4 ft 7 in (1,397 mm) Pivot centres 25 ft 6 in (7,772 mm) Length: ​  • Over couplers 66 ft 5 1⁄4 in (20,250 mm) Height 12 ft 10 in (3,912 mm) Axle load 14 LT 18 cwt (15,140 kg)  • 1st coupled 13 LT 1 cwt (13,260 kg)  • 2nd coupled 13 LT 3 cwt (13,360 kg)  • 3rd coupled 12 LT 11 cwt (12,750 kg)  • 4th coupled 14 LT 16 cwt (15,040 kg)  • 5th coupled 14 LT 14 cwt (14,940 kg)  • 6th coupled 14 LT 18 cwt (15,140 kg)  • Tender bogie Bogie 1: 18 LT 9 cwt (18,750 kg) Bogie 2: 19 LT 10 cwt (19,810 kg)  • Tender axle 9 LT 15 cwt (9,906 kg) Adhesive weight 83 LT 3 cwt (84,480 kg) Loco weight 83 LT 3 cwt (84,480 kg) Tender weight 37 LT 19 cwt (38,560 kg) Total weight 121 LT 2 cwt (123,000 kg) Tender type 2-axle bogies Fuel type Coal Fuel capacity 7 LT (7.1 t) Water cap 3,000 imp gal (14,000 l) Tender cap 6 LT (6.1 t) Firebox type Belpaire  • Firegrate area 34 sq ft (3.2 m2) Boiler: ​  • Pitch 7 ft 2 in (2,184 mm)  • Diameter 5 ft (1,524 mm)  • Tube plates 13 ft 9 5⁄8 in (4,207 mm)  • Small tubes 239: 2 in (51 mm) Boiler pressure 180 psi (1,241 kPa) Safety valve Ramsbottom Heating surface 1,863 sq ft (173.1 m2)  • Tubes 1,727 sq ft (160.4 m2)  • Firebox 136 sq ft (12.6 m2) Cylinders Four Cylinder size 16 in (406 mm) bore 24 in (610 mm) stroke Valve gear Walschaerts Couplers Johnston link-and-pin

Performance figures Tractive effort 34,560 lbf (153.7 kN) @ 75%

Career Operators Central South African Railways South African Railways Transvaal Collieries Class CSAR Class M, SAR Class KM Number in class 1 Numbers CSAR 1000, SAR 1600 Delivered 1904 First run 1904 Withdrawn 1918

The South African Railways Class KM 0-6-0+0-6-0 of 1904 was an articulated steam locomotive from the pre-Union era in Transvaal Colony.

In 1904, the Central South African Railways placed a single 0-6-0+0-6-0 Kitson-Meyer type articulated steam locomotive in service and designated it Class M. In 1912, when the locomotive was assimilated into the South African Railways, it was renumbered and designated Class KM.

In 1903, the English locomotive builders Kitson and Company persuaded the Cape Government Railways (CGR), the Beira and Mashonaland Railway (B&MR) and the Central South African Railways (CSAR) to try their new 0-6-0+0-6-0 Kitson-Meyer type articulated steam locomotive. One was delivered to the CGR and two to the B&MR in 1903. One locomotive was also delivered to the CSAR in 1904, numbered 1000 and designated Class M.

The Kitson-Meyer design consisted of two sets of coupled wheels under the frame, with both power units free to swivel in relation to the frame. Compared to the usual practice on steam locomotives, the sets of coupled wheels were both mounted back to front, with the wheels to the front of the cylinders. The cylinders of the rear power unit discharged their exhaust steam up a chimney mounted in the coal bunker to the rear of the cab, while the front cylinders discharged in the usual manner up a chimney mounted on the smokebox in front of the boiler.

The Kitson-Meyer was a development of the Meyer locomotive. On a Meyer locomotive, the two engine units were mounted close together, and usually with the cylinder ends of the engine units facing each other at the centre of the locomotive. One disadvantage of this design was that the rear power unit was directly beneath the firebox, thereby limiting the firebox in size.

On the Kitson-Meyer locomotive, the rear engine unit was located further back, which allowed the firebox to be between the two engine units, thereby making a much larger firebox possible. The same feature would also be a characteristic of the Garratt locomotive, of which the first appearance in the world was still five years in the future at the time. This also increased the length of the locomotive, making it possible to utilise the additional length behind the cab for a coal and water bunker. The auxiliary chimney at the rear avoided the need to have an exhaust steam pipe running the length of the locomotive to the smokebox at the front end.