| South African Class 16D 4-6-2 | |
|---|---|
| "Big Bertha" 860 on the "Union Limited", Paarl, circa 2001 | |
| Power type | Steam |
| Designer | South African Railways |
| Builder | Baldwin Locomotive Works |
| Serial number | 58309-58310, 58703-58707[1] |
| Model | Class 16D |
| Build date | 1925-1926 |
| Total produced | 7 |
| Configuration | 4-6-2 "Pacific" |
| Gauge | 3 ft 6 in (1,067 mm) Cape gauge |
| Leading wheel diameter |
30 in (762 mm) |
| Driver diameter | 60 in (1,520 mm) as built 63 in (1,600 mm) rewheeled |
| Trailing wheel diameter |
33 in (838 mm) |
| Wheelbase | Total: 60 ft 3.1875 in (18.369 m) Engine: 6 ft 10 in (2.083 m) pilot 11 ft (3.353 m) coupled 30 ft 8 in (9.347 m) total Tender: 6 ft 2 in (1.880 m) bogie 20 ft 5 in (6.223 m) total |
| Length | 68 ft 2.1875 in (20.782 m) total |
| Height | 12 ft 10 in (3.912 m) as built 12 ft 11.5 in (3.950 m) rewheeled |
| Frame | Bar frame |
| Axle load | 18.75 long tons (19.1 t) per driver as built 19.4 long tons (19.7 t) rewheeled |
| Weight on drivers | 56.25 long tons (57.2 t) as built 57.5 long tons (58.4 t) rewheeled |
| Locomotive weight | 89.6 long tons (91.0 t) as built 90.55 long tons (92.0 t) w/o rewheeled |
| Tender weight | 68,888 lb (31.2 t) empty 69.4 long tons (70.5 t) w/o |
| Locomotive & tender combined weight |
183,828 lb (83.4 t) empty 159 long tons (161.6 t) w/o as built 159.95 long tons (162.5 t) w/o rewheeled |
| Tender type | KT * 2 axle bogies * Wheels 34 in (864 mm) dia * Length 28 ft 8.25 in (8.744 m) |
| Fuel type | Coal |
| Fuel capacity | 14 long tons (14.2 t) |
| Water capacity | 6,000 imp gal (27,000 l) |
| Boiler | 5 ft 10.25 in (1.784 m) int dia 17 ft 10.375 in (5.445 m) int length 8 ft 6 in (2.591 m) pitch as built 8 ft 7.5 in (2.629 m) pitch rewheeled |
| Boiler pressure | 195 psi (1,340 kPa) |
| Firegrate area | 45 sq ft (4.181 m2) |
| Heating surface: Tubes |
181 tubes 2 in (50.8 mm) ext dia 30 tubes 5.375 in (137 mm) ext dia 2,453 sq ft (227.891 m2) |
| Heating surface: Flues |
22 sq ft (2.044 m2) |
| Heating surface: Firebox |
164 sq ft (15.236 m2) |
| Heating surface: Total |
2,686 sq ft (249.538 m2) |
| Superheater area | 593 sq ft (55.092 m2) |
| Cylinders | Two |
| Cylinder size | 23 in (584 mm) bore 26 in (660 mm) stroke |
| Valve gear | Walschaerts |
| Tractive effort | At 75% boiler pressure: 33,530 lbf (149.1 kN) as built 33,570 lbf (149.3 kN) rewheeled[1][2] |
| Career | South African Railways |
| Class | Class 16D |
| Number in class | 7 |
| Number | 860-866 |
| Nicknames | Big Bertha |
| Delivered | 1925-1926 |
| First run | 1925 |
| Withdrawn | 1972 |
| Disposition | Retired |
In 1925 the South African Railways placed two Class 16D locomotives with a 4-6-2 Pacific wheel arrangement in passenger train service. Five more were placed in service in 1926.[2]
Contents |
The Class 16D 4-6-2 Pacific type locomotive was built for the South African Railways (SAR) in the United States by Baldwin Locomotive Works. Two were built and delivered in 1925, numbered 860 and 861, along with the first two Class 15CB from the same manufacturer. They were followed by another five Pacifics from the same manufacturer in 1926, numbered 862 to 866. The locomotives were specially designed for working the Union Limited and Union Express fast passenger trains, the forerunners of the Blue Train, between Johannesburg and Cape Town.[1][3]
The builders conformed to SAR requirements as far as practicable, but also incorporated the latest American railway engineering practices. The Class 16D and Class 15CB locomotives introduced several features which were new to the SAR at the time, such as top feeds to the boiler, self cleaning smokeboxes, Sellar’s drifting valves and grease lubrication. Their fireboxes were equipped with siphon tubes to support the brick arch and to improve circulation.[1][3]
The Class 16D had a bar frame extending from the front buffer beam to the rear dragbox, compared to its successor Class 16DA which had a main frame that terminated behind the rear drivers, behind which it had a built-up wide section under the firebox that gave it more ashpan room.[4]
The locomotive’s size quickly earned it the nickname "Big Bertha", while its contemporary Class 15CB heavy goods locomotive that arrived from the same builders in the same shipment was nicknamed "Big Bill".[3]
Like the subsequent Class 16DA they were all delivered with 60 inches (1,520 millimetres) driving wheels. All seven Class 16D locomotives were later refitted with 63 inches (1,600 millimetres) driving wheel tyres, similar to the modification that was also done on Class 16C numbers 821 and 825.[2]
The Class 16D Pacifics were initially placed in passenger service out of Johannesburg on the Kimberley line all the way through to Beaufort West in the Karoo. On Thursday 13 August 1926 "Big Bertha" number 860 made locomotive history by hauling the Union Limited, later to become the Blue Train, over a distance of 956 miles (1,539 kilometres) from Johannesburg to Cape Town in 29 hours.[1][3]
This continuous run by one locomotive set up a world record. Prior to this, up to six locomotives were used to make this run, with locomotive changes at Klerksdorp, Kimberley, De Aar, Beaufort West and Touws River. On the return journey, number 860 took the Union Limited over at Beaufort West and hauled it all the way back to Johannesburg.[1][3]
With the arrival of larger locomotives they were transferred to Bloemfontein in the Orange Free State, from where they worked north to Johannesburg. In the late 1930s they were relocated to Cape Town, from where they hauled fast locals to Wellington and Malmesbury for the remainder of their careers. They were retired in 1972.[1][3]
The main picture shows "Big Bertha" number 860 piloting Class 16DA number 879 on the "Union Limited" at Paarl, Western Cape, circa 2001.
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