South African Class 14C 4-8-2, 4th batch
Class 14CM, fourth batch, possibly no. 2028, c. 1945
|The leading coupled axle had flangeless wheels|
The South African Railways Class 14C 4-8-2 of 1922 was a steam locomotive.
In 1922, the South African Railways placed the fourth and last batch of thirteen Class 14C steam locomotives with a 4-8-2 Mountain type wheel arrangement in service to bring the total in the class to 73. All four batches had different maximum axle loadings. Through reboilerings, rebalancings and cylinder bushings during its service life, this single class eventually ended up as six distinct locomotive classes with two boiler types and a multitude of axle loading and boiler pressure configurations.
In 1922, the last thirteen Class 14C locomotives were ordered from the Montreal Locomotive Works (MLW) in Canada. They were delivered in that same year and numbered in the range from 2026 to 2038. Of the four batches built which all differed in terms of maximum axle loading, weight on driving wheels and engine weight, the engines of 1922 were the heaviest.
The Class 14C was ordered at a time when further orders of the earlier Class 14 models were unobtainable from manufacturers in the United Kingdom. The Canadian manufacturer undertook to supply engines of equivalent power, wheelbase and weight, but to their own design. As a result, bar frames substituted plate frames and several other important modifications were made.
As built, the locomotives of the fourth batch were heavier than all three previous batches, 6 long tons 7 hundredweight (6,452 kilograms) heavier than the first, 7 long tons 11 hundredweight (7,671 kilograms) heavier than the second and 5 long tons 17 hundredweight (5,944 kilograms) heavier than the third. All four batches were delivered with Type LP tenders with a coal capacity of 10 long tons (10.2 tonnes) and a water capacity of 4,250 imperial gallons (19,300 litres).
Modifications and reclassifications
Watson Standard boilers
During the 1930s, many serving locomotives were reboilered with a standard boiler type designed by A.G. Watson, CME of the SAR at the time, as part of his standardisation policy. Such Watson Standard reboilered locomotives were reclassified by adding an "R" suffix to their classification.
All thirteen locomotives were eventually reboilered with Watson Standard no. 2 boilers and reclassified to Class 14CR. Only slight alterations were necessary to the engine frames. With the new boilers, the side running boards and platforms were attached to the engine frames instead of to the boilers as in the original design. In the process, the boiler pitch was raised from 7 feet 7 inches (2,311 millimetres) to 8 feet 1 1⁄2 inches (2,476 millimetres), which raised the chimney height from 12 feet 9 3⁄8 inches (3,896 millimetres) to 13 feet 3⁄4 inch (3,981 millimetres). This exceeded the loading gauge height of 13 feet (3,962 millimetres) above the railhead.
Their original Belpaire boilers were fitted with Ramsbottom safety valves, while the Watson Standard boilers were fitted with Pop safety valves. The reboilered engines were also equipped with Watson cabs with their distinctive slanted fronts, compared to the conventional vertical fronts of their original cabs, to allow easier access to the firebox stays. The footplate was also modified to conform to SAR standard practice. Early conversions were equipped with copper and later conversions with steel fireboxes.
Around 1930, the question of maximum axle loads for locomotives was thoroughly investigated by the Mechanical and Civil Engineering Departments of the SAR. It was found that, among some other locomotive classes, the Class 14C had a rather severe vertical hammer blow effect on the track when running at speed due to an undue proportion of the reciprocating parts being balanced. Modifications were accordingly made to the Class 14C.
The locomotives had weights attached between the frames to increase adhesion. Over time, most of the Class 14C family of locomotives were "rebalanced" by having these weights increased or reduced to redistribute, increase or reduce the axle loading and adhesive weight, by altering the loads on the individual coupled wheels, leading bogies and trailing pony trucks. Coupled wheel axle loading adjustment was achieved by attaching steel boxes, filled with an appropriate amount of lead, over each axle between the frames.
Since they were too heavy for use on light track, the fourth batch version of the rebalanced locomotives was reclassified to Class 14CM, with the "M" indicating mainline service. Twelve of these locomotives, all except no. 2035, were rebalanced and reclassified to Class 14CM. The boiler pressure setting of rebalanced locomotives of the fourth batch was not altered and remained at 190 pounds per square inch (1,310 kilopascals). It is not clear which of these reboilering and rebalancing modifications were carried out first, one, the other, either one or together, but in whichever order, all twelve rebalanced locomotives were eventually also reboilered with Watson Standard no. 2 boilers and reclassified to Class 14CRM.
Several of the locomotives had their cylinders bushed to reduce the bore from the as-built 22 to 21 3⁄4 inches (559 to 552 millimetres). At the same time, the boiler pressure setting of the Classes 14C and 14CR locomotives was adjusted upwards from 190 to 195 pounds per square inch (1,310 to 1,344 kilopascals) to keep their tractive effort more or less unaffected by the reduction in piston diameter. The boiler pressure setting of the mainline Classes 14CM and 14CRM was adjusted upwards from 190 to 193 pounds per square inch (1,310 to 1,331 kilopascals).
The Class 14C was placed in service on the Cape Eastern system, working on the mainline to Cookhouse. Some went to the Cape Western system, where they banked up the Hex River Pass from De Doorns.
|Wikimedia Commons has media related to South African Class 14C 4-8-2, 4th batch.|
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