South African Class 16DA 4-6-2 1928

The South African Railways Class 16DA 4-6-2 of 1928 was a steam locomotive.
In 1928, the South African Railways placed six Class 16DA steam locomotives with a 4-6-2 Pacific type wheel arrangement in passenger train service. Eight more entered service in 1929.
==Manufacturers==
Further orders for locomotives similar to the Class 16D Pacific type locomotive were placed for the South African Railways (SAR) in 1928. The design of the earlier engines was modified by the Chief Mechanical Engineer (CME), Colonel F.R. Collins DSO, along the same lines as his design of the Class 15CA Mountain type.
This consisted of a locomotive bar frame which was shorter to end at the front of the firebox, with a bridle casting to create a widened frame extension below the firebox and the cab to the rear dragbox to gain more ashpan room under the firebox.
These redesigned locomotives were designated Class 16DA and were built by two manufacturers in 1928 and 1929. The first six, numbered in the range from 868 to 873, were built in Germany by Hohenzollern Locomotive Works and entered service in 1928. Another eight locomotives, numbered in the range from 843 to 850, were built in the United States of America by Baldwin Locomotive Works and entered service in 1929.
==Characteristics==
The Hohenzollern and Baldwin-built Class 16DA locomotives basically differed from the predecessor Class 16D only by virtue of its shortened frame and bridle casting, the Class 16D having had a frame extending all the way from the front buffer beam to the rear dragbox. They used the same Type KT tenders with a coal capacity of 14 long tons (14.2 tonnes) and a water capacity of 6,000 imperial gallons (27,300 litres). As delivered, they had 60 inches (1,524 millimeters) diameter coupled wheels and their cylinders were of 22 inches (559 millimeters) bore and 26 inches (660 millimeters) stroke. Their boiler operating pressure was set at 195 pounds per square inch (1,344 kilopascals).
==Modification==
During the 1940s six of these locomotives, three from each manufacturer group, were retyred with 63 inches (1,600 millimeters) diameter tyres on their coupled wheels. To not have their tractive effort reduced by the larger coupled wheels, their cylinders were reamed from a bore of 22 to 23 inches (559 to 584 millimeters) and their operating boiler pressure was raised to 205 pounds per square inch (1,410 kilopascals). All the modified locomotives remained classified as Class 16DA.
When the larger tyres were fitted, the old tyres were left in position and turned down on the wheel centers to serve as liners and the new tyres were then shrunk on over the liners. The practice of increasing the diameter of coupled wheels, wheel spacing and other considerations permitting, was begun by A.G. Watson during his term in office as CME and was continued by his successors. The reduction of tractive effort caused by the larger wheels was made up by increasing boiler pressures or by fitting larger cylinders or both, as required. This policy resulted in more mileage between heavy repairs, less cost-per-mile on repairs and locomotives capable of higher speeds.
==Service==
The Class 16DA Pacifics were initially placed in passenger service between Johannesburg and Kimberley where they regularly worked trains like the Union Express and Union Limited, which became the Blue Train after the Second World War. From 1930 the new Henschel-built wide-firebox Class 16DA took over this duty.
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In 1939–1940, when new air-conditioned rolling stock was placed in service on the Union Limited and Union Express services between Cape Town and Johannesburg, all the Class 16DA and Class 16E locomotives were transferred to Bloemfontein in the Orange Free State. From here, they continued to work passenger trains north and south, including the Orange Express, until the Class 15F replaced them and they were relegated to suburban and local passenger train work. By the early 1950s, the suburban trains to Lynchfield and Melorane were handled by narrow-firebox Class 16DA locomotives which only occasionally worked mainline passenger trains by then. They were withdrawn from service in 1973.
Four of the Baldwin-built locomotives were sold into industrial service. No. 844 went to Hlobane Colliery in Natal and later to Umgala Colliery. Numbers 845, 847 and 848 went to Wankie Colliery in Rhodesia, where they became numbers 5 to 7 in reverse order. After they were finally withdrawn in 1982, one of these three was plinthed alongside the main North road at Hwange. Another of the Baldwin-built locomotives, no. 850, is plinthed at Theunissen in the Free State.
==Works numbers==
The table lists the Hohenzollern and Baldwin Class 16DA engine numbers, builders, years built, works numbers and variations in coupled wheel sizes.
Class 16DA 4-6-2Builders, Works Numbers & Variations
SAR No.	Builder 	Year	WorksNo.	Coupledwheel dia.
843 	Baldwin 	1929	60820 	63"/1600mm
844 	Baldwin 	1929	60821 	60"/1524mm
845 	Baldwin 	1929	60822 	60"/1524mm
846 	Baldwin 	1929	60823 	63"/1600mm
847 	Baldwin 	1929	60824 	60"/1524mm
848 	Baldwin 	1929	60825 	63"/1600mm
849 	Baldwin 	1929	60826 	60"/1524mm
850 	Baldwin 	1929	60827 	60"/1524mm
868 	Hohenzollern	1928	4653 	63"/1600mm
869 	Hohenzollern	1928	4654 	63"/1600mm
870 	Hohenzollern	1928	4655 	60"/1524mm
871 	Hohenzollern	1928	4656 	60"/1524mm
872 	Hohenzollern	1928	4657 	60"/1524mm
873 	Hohenzollern	1928	4658 	63"/1600mm
==Preservation==
Number	Works nmr	THF / Private	Leaselend / Owner 	Current Location 	Outside SOUTH AFRICA	?
848 	 	Private 	Wanki Collery 	Main Street 	Zimbabwe 	next to Wanki Highway
850 	 	Private 	Theunissen Municipality 	Main Street 	 	
870 	 	THF 	 	Krugersdorp Locomotive Depot 	 	
876 	 	THF 	Transnet Heritage Foundation (Museum)	Bloemfontein Locomotive Depot	 	
878 	 	THF 	Transnet Engineering 	Bloemfontein Locomotive Depot	 	
879 	 	THF 	Ceres Railway Company 	Cape Town Station 	 	
==Gallery==
File:SAR Class 16DA 850 (4-6-2).jpg|Baldwin-built no. 850 at Theunissen, 29 May 2005
File:Class16DA844.jpg|Baldwin-built no. 844 at the SANRASM South Site, June 2011
Category:4-6-2 locomotives
Category:4-6-2 steam locomotives
Category:Tender locomotives
Category:Steam locomotives
Category:South African