South African Class 18 2-10-2
Encyclopedia
In December 1927 and January 1928 the South African Railways placed two Class 18 steam locomotive
s with a 2-10-2
wheel arrangement in service.
in Germany who delivered two locomotives in 1927 and 1928, numbered 1360 and 1361. They were very powerful three cylinder locomotives, with their two outer cylinders using Walschaerts valve gear and the inner cylinder using Gresley conjugated valve gear
that was actuated by the motions of the outer cylinders.
When delivered, the third cylinder was clearly visible, but subsequent plating below the smokebox hid it from view. These were the most powerful non-articulated locomotives to see service on the SAR, having a tractive effort of no less than 53650 pound-forces (238.647 kN) at 75% boiler pressure, capable of hauling loads of 1800 long tons (1,828.9 t) over the ruling gradient of 1 in 100 on the Witbank-Apex section.
Contemporary Henschel publicity appropriately referred to them as the "Henschel Giants". They were larger in most respects than Deutsche Reichsbahn
’s new Standard gauge
Class 44
three cylinder 2-10-0 locomotives. Although their all-up locomotive weight was almost the same, when considering the fact that the SAR’s Cape gauge
Class 18 had shorter axles and frame strethers, saving weight that could then be built into other items such as the firebox, the Class 18 was the larger locomotive.
In order to allow the locomotive to negotiate curves of 320 feet (97.536 m) radius despite its long coupled wheelbase, the third and fourth pairs of driving wheels were flangeless. In addition, the locomotive made use of a Krauss-Helmholtz bogie
system, where the leading pair of driving wheels has a limited amount of sideplay with an articulated link to the leading bissel bogie
. The bissel bogie was connected to a sleeve around the first driving axle so that any displacement of the bissel bogie in one direction would cause a similar displacement of the leading driving axle in the opposite direction, thereby steering the driving wheels through curves.
The outside cylinders drove the third pair of driving wheels while the inside cylinder drove the second pair through a cranked axle with the cylinder mounted in an inclined position. The three cranks were arranged at an angle of 120 degrees to each other, allowing for the inclination of the inner cylinder.
and Germiston, where the Class MF
Mallets were considered as being too sluggish and the hauling capacity of the non-articulated fleet was being stretched to the limit of their capacity.
In spite of the two sets of flangeless driving wheels and the Krauss-Helmholtz system, the Class 18 experienced excessive flange and tyre wear. In addition, the complicated valve gear was not robust enough and required high maintenance, frequently giving trouble owing to wear and breakage. The result was that the locomotives had to be shopped at under 40000 miles (64,374 km). Both Class 18 locomotives were retired by 1951.
Steam locomotive
A steam locomotive is a railway locomotive that produces its power through a steam engine. These locomotives are fueled by burning some combustible material, usually coal, wood or oil, to produce steam in a boiler, which drives the steam engine...
s with a 2-10-2
2-10-2
Under the Whyte notation for the classification of steam locomotives, 2-10-2 represents the wheel arrangement of two leading wheels on one axle, usually in a leading truck, ten powered and coupled driving wheels on five axles, and two trailing wheels on one axle, usually in a trailing truck...
wheel arrangement in service.
Manufacturer
The Class 18 2-10-2 steam locomotive was designed by Colonel F.R. Collins, Chief Mechanical Engineer (CME) of the South African Railways (SAR) from 1922 to 1929, and built by Henschel and SonHenschel & Son
Henschel & Son was a German company, situated in Kassel, best known during the 20th century as a maker of transportation equipment, including locomotives, trucks, buses and trolleybuses, and armoured fighting vehicles and weapons....
in Germany who delivered two locomotives in 1927 and 1928, numbered 1360 and 1361. They were very powerful three cylinder locomotives, with their two outer cylinders using Walschaerts valve gear and the inner cylinder using Gresley conjugated valve gear
Gresley conjugated valve gear
The Gresley conjugated valve gear is a valve gear for steam locomotives designed by Sir Nigel Gresley, chief mechanical engineer of the LNER, assisted by Harold Holcroft...
that was actuated by the motions of the outer cylinders.
When delivered, the third cylinder was clearly visible, but subsequent plating below the smokebox hid it from view. These were the most powerful non-articulated locomotives to see service on the SAR, having a tractive effort of no less than 53650 pound-forces (238.647 kN) at 75% boiler pressure, capable of hauling loads of 1800 long tons (1,828.9 t) over the ruling gradient of 1 in 100 on the Witbank-Apex section.
Contemporary Henschel publicity appropriately referred to them as the "Henschel Giants". They were larger in most respects than Deutsche Reichsbahn
Deutsche Reichsbahn
Deutsche Reichsbahn was the name of the following two companies:* Deutsche Reichsbahn, the German Imperial Railways during the Weimar Republic, the Third Reich and the immediate aftermath...
’s new Standard gauge
Standard gauge
The standard gauge is a widely-used track gauge . Approximately 60% of the world's existing railway lines are built to this gauge...
Class 44
DRG Class 44
The Class 44 was a ten-coupled, heavy goods train steam locomotive built for the Deutsche Reichsbahn as a standard steam engine class . Its sub-class was G 56.20 and it had triple cylinders...
three cylinder 2-10-0 locomotives. Although their all-up locomotive weight was almost the same, when considering the fact that the SAR’s Cape gauge
Cape gauge
Cape gauge is a track gauge of between the inside of the rail heads and is classified as narrow gauge. It has installations of around .The gauge was first used by Norwegian engineer Carl Abraham Pihl and the first line was opened in 1862.- Nomenclature :...
Class 18 had shorter axles and frame strethers, saving weight that could then be built into other items such as the firebox, the Class 18 was the larger locomotive.
Characteristics
The Class 18 had a round topped boiler and a firebox with a combustion chamber, with arch tubes supporting the brick arch.In order to allow the locomotive to negotiate curves of 320 feet (97.536 m) radius despite its long coupled wheelbase, the third and fourth pairs of driving wheels were flangeless. In addition, the locomotive made use of a Krauss-Helmholtz bogie
Krauss-Helmholtz bogie
A Krauss-Helmholtz bogie is a mechanism used on a steam locomotive, where a carrying axle is connected to a coupled axle via a lever such that when the carrying axle swings to the side on going round a curve, it causes the coupled axle to move sideways in the opposite direction...
system, where the leading pair of driving wheels has a limited amount of sideplay with an articulated link to the leading bissel bogie
Bissel bogie
A Bissel truck is a very simple and commonly used way of designing a carrying axle on a steam locomotive to enable it to negotiate curves more easily. The design uses a single-axled bogie, usually known as a pony truck, whose pivot is towards the centre of the locomotive...
. The bissel bogie was connected to a sleeve around the first driving axle so that any displacement of the bissel bogie in one direction would cause a similar displacement of the leading driving axle in the opposite direction, thereby steering the driving wheels through curves.
The outside cylinders drove the third pair of driving wheels while the inside cylinder drove the second pair through a cranked axle with the cylinder mounted in an inclined position. The three cranks were arranged at an angle of 120 degrees to each other, allowing for the inclination of the inner cylinder.
Service
The Class 18 was introduced in an attempt to ease problems that were being experienced with increasingly heavy coal trains on the line between WitbankWitbank
Witbank , also known as eMalahleni is a city situated on the Highveld of Mpumalanga, South Africa, within the eMalahleni Local Municipality. The name Witbank is Afrikaans for White Ridge and is named after a white sandstone outcrop where wagon transport drivers rested...
and Germiston, where the Class MF
South African Class MF 2-6-6-2
In 1911 the Central South African Railways placed nine Mallet articulated compound steam locomotives with a 2-6-6-2 wheel arrangement in service. In 1912, when they were assimilated into the South African Railways, they were renumbered and classified as Class MF...
Mallets were considered as being too sluggish and the hauling capacity of the non-articulated fleet was being stretched to the limit of their capacity.
In spite of the two sets of flangeless driving wheels and the Krauss-Helmholtz system, the Class 18 experienced excessive flange and tyre wear. In addition, the complicated valve gear was not robust enough and required high maintenance, frequently giving trouble owing to wear and breakage. The result was that the locomotives had to be shopped at under 40000 miles (64,374 km). Both Class 18 locomotives were retired by 1951.
Gallery
The main picture shows a Class 18 locomotive at Germiston loco, with plating below the smokebox hiding the third cylinder.See also
- Tender locomotive numbering and classification
- The 2-10-2 "Santa Fe"
- List of South African locomotive classes