South African Class 16E 4-6-2

The South African Railways Class 16E 4-6-2 of 1935 was a steam locomotive.

In 1935, the South African Railways placed six Class 16E steam locomotives with a 4-6-2 Pacific type wheel arrangement in express passenger train service.^[1][2][3]

Manufacturer

Following the world depression of 1930-1933, the South African Railways (SAR) set out to improve its Cape Town-Johannesburg express passenger service. To attain higher average speeds for its more important express trains, the Class 16E 4-6-2 Pacific type locomotive was designed by A.G. Watson, Chief Mechanical Engineer (CME) of the SAR from 1929 to 1936, specifically for use with the Union Express and the Union Limited trains. Six locomotives were built by Henschel and Son in Kassel, Germany, and delivered in 1935, numbered in the range from 854 to 859.^[1][2][3][4]

Characteristics

With its 72 inches (1,830 millimetres) diameter coupled wheels, the Class 16E was considered the most remarkable Cape gauge express passenger locomotive ever built. It boasted the largest fire grate on any Pacific outside North America. The coupled wheels were the largest ever used on any less than 4 feet 8 ¹⁄₂ inches (1,435 millimetres) standard gauge locomotive, and it had an all-up weight and tractive effort equal to or exceeding that of most Pacifics outside North America.^[1][2][5]

A.G. Watson

Watson experienced considerable difficulty to keep the axle loads within the permissible limits specified by the Chief Civil Engineer, with the result that the ashpan, cab, side running boards and several other parts were made of thinner material than usual. Even the original number plates were cast in aluminium. Still, the axle load of 20 long tons 19 hundredweight (21,290 kilograms) was the greatest of any engine or vehicle on the SAR at the time.^[2]

The locomotive introduced the Type JT tender, with a coal capacity of 14 long tons (14.2 tonnes), a water capacity of 6,000 imperial gallons (27,300 litres) and an axle load of 17 long tons 15 hundredweight (18,030 kilograms).^[1][2]

The main bar frames were machined from rolled steel slabs and each frame was in one piece from the front to the hind buffer beam. The wheels were fitted with hollow crank pins, while the leading bogie was fitted with an oil bath centre pivot. The connecting and coupling rods were fitted with floating bronze bushes and were made of special chrome-nickle alloy steel of fluted section. The centre set of coupled wheels were flangeless and had wider treads than the other two sets, to prevent them from slipping off the rails in sharp curves.^[2]

To obtain increased tractive effort with the large coupled wheels, larger cylinders of 24 inches (610 millimetres) bore by 28 inches (711 millimetres) stroke were used. These, at a boiler pressure of 210 pounds per square inch (1,448 kilopascals), gave the locomotive a tractive effort of 35,280 pounds-force (156.9 kilonewtons) at 75% of boiler pressure. Each cylinder was cast integral with a half smokebox saddle, which made each casting interchangeable.^[2]

The drive shafts which turn the poppet valve camshafts are no different from those found under most rear wheel drive cars and trucks

Given the successful operation of rotary cam poppet valve gear on the Class 19C, it was also used on the Class 16E. The valves were driven by outside rotary propshafts from turning mechanisms mounted on the driving coupled wheels. The valves were double-seated and housed at each end of the cylinders, an arrangement which resulted in short and straight ports between the valves and the cylinder barrels. The admission valves were 8 inches (203 millimetres) in diameter and the exhaust valves 9 inches (229 millimetres). Most of the detail parts of the rotary cam gear, particularly the main drive and reversing gear, were interchangeable with similar parts on the Class 19C. The poppet valve gear gave the engine extremely free-running characteristics.^[1][2][5]

The Class 16E was delivered with a Watson Standard no. 3A boiler, one of the range of standard boiler types designed by Watson as part of his standardisation policy. The boiler was designed for a maximum working pressure of 225 pounds per square inch (1,551 kilopascals) and the boiler barrel plates and firebox outer shell were of nickel steel. The boiler and the firebox were entirely clothed with Alfol insulation.^[2][6]

At 9 feet 3 inches (2,819 millimetres) above rail level, the Class 16E boiler centre-line was the highest-pitched on the SAR at the time. Because of this and the limitations of the loading gauge, the boiler was domeless, with an inspection manhole on top of the boiler barrel where the dome would have been. Steam was collected through numerous small feeder pipes fixed into two collector pipes, which were arranged as high as possible above the water surface. The collector pipes then joined together to form a main steam pipe, 7 inches (180 millimetres) in diameter, which led to the superheater header and multiple valve regulator, situated in the smokebox. The steam pipes from the header to each cylinder were 6 inches (150 millimetres) in diameter.^[1][2]

A.G. Watson with his Class 16E, c. 1935

The firebox had a power-operated Ajax fire-door and the grate was of the sectional pin-hole type, fitted with power-operated shaking gear. To assist in keeping within the axle load limits, the ashpan was constructed of relatively thin anti-corrosive steel plates of a special heat-resisting quality. The brick arch was supported by five 3 inches (76 millimetres) diameter arch tubes. The firebox was fitted with SAR standard type flexible stays and, to allow easier access to the stays, the engine was equipped with a Watson cab with its slanted front which, like the Watson Standard boiler, was to become the standard on later SAR steam locomotive classes. The cab was of special light steel and welded throughout.^[2][6]

Service

The Class 16E Pacifics were placed in service at Kimberley and regularly worked trains like the Union Express, which was to become the Blue Train after the Second World War, and the Union Limited southward to Beaufort West and northward to Johannesburg. Although they were never stationed at Braamfontein Loco in Johannesburg, they were serviced there in the process of working between Kimberley and Johannesburg.^[7]

They proved to be very successful, efficient and economical in service, when handling loads within their capacity. When the original wooden-bodied coaches of the Union Express were replaced with heavier steel-bodied air-conditioned coaches in 1939, however, the loads were increased to 600 long tons (610 tonnes) or more, and the Class 16E was considered to be inadequate to the task and relocated to Bloemfontein in the Orange Free State.^[1][2][3][7]

From here, they hauled regular passenger trains, including the Orange Express, working north to Johannesburg and south to De Aar as well as across to Kimberley. When air-conditioned lounge cars were added to trains like the Orange Express and Trans-Karoo, they were again considered as not powerful enough for the additional load and were eventually withdrawn from service in 1972.^[3][7]

Preservation

Two locomotives survive and were still relatively intact by 2015. No. 858, Betty, was stored in the open at Beaconsfield, Kimberley, while no. 857, Ann Smith • Bloemfontein Queen, was in storage at Bloemfontein, parked under cover at the locomotive depot.^[8]

Commemoration

A 20c postage stamp, depicting a Class 16E locomotive, was one of a set of four commemorative postage stamps which were issued by the South African Post Office on 27 April 1983, to commemorate the steam locomotives of South Africa which were rapidly being withdrawn from service at the time. The artwork and stamp design was by the noted stamp designer and artist Hein Botha. The locomotive depicted was Class 16E no. 858 Betty. The outline of a traditional SAR locomotive number plate was used as a commemorative cancellation for De Aar on the date of issue.^[9]

Illustration

Class 16E locomotives were equipped with smoke deflectors in later years.

• 

  No. 854 at Paardeneiland Loco, Cape Town, c. 1935

• 

  No. 854 on the Union Limited near Roodepoort, c. 1936

• 

  No. 858 leaving Johannesburg on the Blue Train, c. 1969

• 

  No. 858 with smoke deflectors at Orange River station, 23 April 1981

• 

  No. 857 with smoke deflectors at Thaba Nchu, 4 July 1999

• 

  No. 858 with smoke deflectors at Beaconsfield, Kimberley, 3 July 1999

References

Wikimedia Commons has media related to South African Class 16E (4-6-2).

Locomotives of South Africa
Steam	7' ¼" gauge East London 0-4-0VB Table Bay 0-4-0ST Table Bay 0-4-0T Table Bay 0-4-0WT 4' 8½" gauge Cape 0-4-0T Blackie Cape 0-4-2 Cape 2-4-0T CGR 0-4-0ST Aid Natal 0-4-0ST Durban Natal 0-4-0WT Natal Natal 4-4-0T Perseverance 3' 6" gauge Tank engines CGR 0-4-0ST 1873 CGR 0-4-0ST 1874 CGR 0-4-0ST 1881 CGR 0-4-0ST 1881 Coffee Pot CGR 0-6-0ST CGR 0-6-0T CGR 2-6-0ST 1900 CGR 2-6-0ST 1902 CGR 1st Class 0-4-0ST 1875 CGR 1st Class 0-4-0ST 1876 CGR 1st Class 2-6-0ST CGR 1st Class 4-4-0T CGR 2nd Class 4-4-0T CGR 3rd Class 2-6-0T CGR Railmotor CSAR Class C CSAR Class E CSAR Rack 4-6-4RT CSAR Railmotor Durban's Congella Durban's Edward Innes Durban's John Milne Durban's Sir Albert Port Elizabeth 0-4-0ST Kowie Railway 0-6-0T Kowie Railway 4-4-0T Metropolitan & Suburban 4-6-2T NGR 2-6-0T Durban & Pietermaritzburg NGR Class I 2-6-2T NGR Class K 0-4-0ST NGR Class K 0-6-0ST NGR Class K 2-6-0T NZASM 10 Tonner NZASM 13 Tonner NZASM 14 Tonner NZASM 18 Tonner NZASM 19 Tonner NZASM 32 Tonner NZASM 40 Tonner PPR 26 Tonner PPR 35 Tonner Portuguese SAR Class A SAR Class B SAR Class C SAR Class C1 SAR Class C2 SAR Class D SAR Class E SAR Class F SAR Class G SAR Class H SAR Class H1 SAR Class H2 SAR Class J SAR Class K SAR Railmotor SAR Dock 0-4-0ST SAR Dock 0-4-0T SWA 2-8-0T 3' 6" gauge Tender engines CGR 1st Class 2-6-0 1876 BP CGR 1st Class 2-6-0 1876 Kitson CGR 1st Class 2-6-0 1879 CGR 1st Class 2-6-0 1891 CGR 1st Class 4-4-0 CGR 1st Class 4-4-0TT CGR 2nd Class 2-6-2TT CGR 3rd Class 4-4-0 1883 CGR 3rd Class 4-4-0 1884 CGR 3rd Class 4-4-0 1889 CGR 3rd Class 4-4-0 1898 CGR 3rd Class 4-4-0 1901 CGR 3rd Class 4-4-0 1903 CGR 4th Class 4-4-2 CGR 4th Class 4-6-0TT 1880 CGR 4th Class 4-6-0TT 1882 CGR 4th Class 4-6-0TT 1882 Joy CGR 4th Class 4-6-0TT 1884 CGR 5th Class 4-6-0 1890 CGR 5th Class 4-6-0 1891 NGR Havelock NGR Class I SAR Class Exp 1 SAR Class Exp 2 SAR Class Exp 3 SAR Class Exp 4 SAR Class Exp 5 SAR Class Exp 6 SAR Class S SAR Class S1 SAR Class S2 SAR Class 1 SAR Class 1A SAR Class 1B SAR Class 2 SAR Class 2C SAR Class 3 SAR Class 3A SAR Class 3B SAR Class 4 SAR Class 4A SAR Class 5 SAR Class 5A SAR Class 5B SAR Class 6 SAR Class 6A SAR Class 6B SAR Class 6C SAR Class 6D SAR Class 6E SAR Class 6F SAR Class 6G SAR Class 6H SAR Class 6J SAR Class 6K SAR Class 6L SAR Class 6Y SAR Class 6Z SAR Class 7 SAR Class 7A SAR Class 7B SAR Class 7C SAR Class 7D SAR Class 7E SAR Class 7F SAR Class 8 SAR Class 8A SAR Class 8B SAR Class 8C SAR Class 8D SAR Class 8E SAR Class 8F SAR Class 8R SAR Class 8X SAR Class 8Y SAR Class 8Z SAR Class 9 SAR Class 10 SAR Class 10A SAR Class 10B SAR Class 10C SAR Class 10D SAR Class 11 SAR Class 12 SAR Class 12A SAR Class 12B SAR Class 13 SAR Class 14 SAR Class 14A SAR Class 14B SAR Class 14C 1st SAR Class 14C 2nd SAR Class 14C 3rd SAR Class 14C 4th SAR Class 15 SAR Class 15A SAR Class 15B SAR Class 15C SAR Class 15CA SAR Class 15E SAR Class 15F SAR Class 16 SAR Class 16A SAR Class 16B SAR Class 16C SAR Class 16D SAR Class 16DA 1928 SAR Class 16DA 1930 SAR Class 16E SAR Class 17 SAR Class 18 SAR Class 19 SAR Class 19A SAR Class 19B SAR Class 19C SAR Class 19D SAR Class 20 SAR Class 21 SAR Class 23 SAR Class 24 SAR Class 25 SAR Class 25NC SAR Class 26 SAR Katanga SWA 2-8-0 3' 6" gauge Articulated engines CGR Fairlie CGR Kitson-Meyer SAR Class FC SAR Class FD SAR Class GA SAR Class GB SAR Class GC SAR Class GCA SAR Class GD SAR Class GDA SAR Class GE SAR Class GEA SAR Class GF SAR Class GG SAR Class GH SAR Class GK SAR Class GL SAR Class GM SAR Class GMA SAR Class GO SAR Class HF SAR Class KM SAR Class MA SAR Class MB SAR Class MC SAR Class MC1 SAR Class MD SAR Class ME SAR Class MF SAR Class MG SAR Class MH SAR Class MJ SAR Class MJ1 SAR Class U 2' 6" gauge Cape Copper John King & Miner Cape Copper Britannia Cape Copper Caledonia Cape Copper Clara Cape Copper Condenser Cape Copper Scotia Namaqua Copper Pioneer Walvis Bay 2-4-2T Hope 2' & 600mm gauges ACR Class NG-G16A CGR NG 0-4-0T CGR NG 0-6-0T CGR NG 4-6-2T CGR Type A 2-6-4T CGR Type C 0-4-0T NGR Class N 4-6-2T SAR Dutton SAR NG 0-4-0T SAR Class NG1 SAR Class NG2 SAR Class NG3 SAR Class NG4 SAR Class NG5 SAR Class NG6 SAR Class NG7 SAR Class NG8 SAR Class NG9 SAR Class NG10 SAR Class NG-G11 SAR Class NG-G12 SAR Class NG-G13 SAR Class NG-G14 SAR Class NG15 SAR Class NG-G16 SWA Class Ha SWA Class Hb SWA Class Hc SWA Class Hd SWA Jung SWA Zwillinge
Electric	Amcoal Class E38 SAR Class ES SAR Class ES1 SAR Class Exp-AC SAR Class 1E SAR Class 2E SAR Class 3E SAR Class 4E SAR Class 5E s1 SAR Class 5E s2 SAR Class 5E s3 SAR Class 5E1 s1 SAR Class 5E1 s2 SAR Class 5E1 s3 SAR Class 5E1 s4 SAR Class 5E1 s5 SAR Class 6E SAR Class 6E1 s1 SAR Class 6E1 s2 SAR Class 6E1 s3 SAR Class 6E1 s4 SAR Class 6E1 s5 SAR Class 6E1 s6 SAR Class 6E1 s7 SAR Class 6E1 s8 SAR Class 6E1 s9 SAR Class 6E1 s10 SAR Class 6E1 s11 SAR Class 7E SAR Class 7E1 SAR Class 7E2 s1 SAR Class 7E2 s2 SAR Class 7E3 s1 SAR Class 7E3 s2 Spoornet Class 7E4 SAR Class 8E SAR Class 9E s1 SAR Class 9E s2 SAR Class 10E SAR Class 10E1 s1 Spoornet Class 10E1 s2 SAR Class 10E2 SAR Class 11E SAR Class 12E Spoornet Class 14E Spoornet Class 14E1 TFR Class 15E Spoornet Class 16E Spoornet Class 17E Spoornet Class 18E s1 TFR Class 18E s2 TFR Class 19E TFR Class 20E TFR Class 21E TFR Class 22E
Gas-electric	SAR Gas-electric
Diesel	3' 6" gauge Diesel-electric PRASA Class Afro 4000 SAR Class DS SAR Class DS1 SAR Class 31-000 SAR Class 32-000 SAR Class 32-200 SAR Class 33-000 SAR Class 33-200 SAR Class 33-400 SAR Class 34-000 SAR Class 34-200 SAR Class 34-400 SAR Class 34-500 SAR Class 34-600 SAR Class 34-800 SAR Class 34-900 SAR Class 35-000 SAR Class 35-200 SAR Class 35-400 SAR Class 35-600 TFR Class 35-800 SAR Class 36-000 SAR Class 36-200 SAR Class 37-000 Spoornet Class 39-000 TFR Class 39-200 TFR Class 43-000 TFR Class 44-000 2' gauge Diesel-electric SAR Class 91-000 3' 6" gauge Diesel-hydraulic SAR Class 61-000 3' 6" gauge Electro-diesel Spoornet Class 38-000
List of South African locomotive classes South African locomotive numbering and classification

South African steam locomotive tenders
Cape gauge	Type CL Type CZ Type ET Type ET1 Type EW Type EW1 Type EW2 Type FT Type GT Type HT Type JT Type JT1 Type JV Type KT Type LP Type MP Type MP1 Type MR Type MS Type MT Type MT1 Type MT2 Type MX Type MY Type MY1 Type SH Type SK Type TJ Type TL Type TM Type WE Type WG Type X-17 Type X-20 Type XC Type XC1 Type XD Type XE Type XE1 Type XF Type XF1 Type XF2 Type XJ Type XM Type XM1 Type XM2 Type XM3 Type XM4 Type XP1 Type XS Type YB Type YC Type YE Type YE1 Type ZA Type ZB Type ZC Type ZE
List of South African locomotive classes South African locomotive history