South African Class 16E 4-6-2

South African Class 16E 4-6-2

No. 858 Betty at Vetrivier, 5 November 1979

Type and origin Power type Steam Designer South African Railways (A.G. Watson) Builder Henschel and Son Serial number 22583-22588 Model Class 16E Build date 1935 Total produced 6

Specifications Configuration 4-6-2 (Pacific) Driver 2nd coupled axle Gauge 3 ft 6 in (1,067 mm) Cape gauge Leading dia. 34 in (864 mm) Coupled dia. 72 in (1,829 mm) Trailing dia. 34 in (864 mm) Tender wheels 34 in (864 mm) Wheelbase 63 ft 5 3⁄16 in (19,334 mm)  • Engine 33 ft 7 in (10,236 mm)  • Leading 7 ft 2 in (2,184 mm)  • Coupled 12 ft 3 1⁄2 in (3,746 mm)  • Tender 20 ft 5 in (6,223 mm)  • Tender bogie 6 ft 2 in (1,880 mm) Length: ​  • Over couplers 71 ft 8 3⁄16 in (21,849 mm) Height 13 ft (3,962 mm) Frame type Bar Axle load 20 LT 19 cwt (21,290 kg)  • Leading 19 LT 14 cwt (20,020 kg)  • 1st coupled 19 LT 8 cwt (19,710 kg)  • 2nd coupled 20 LT 19 cwt (21,290 kg)  • 3rd coupled 19 LT 7 cwt (19,660 kg)  • Trailing 18 LT 7 cwt (18,640 kg)  • Tender bogie Bogie 1: 33 LT 18 cwt (34,440 kg) Bogie 2: 35 LT 10 cwt (36,070 kg)  • Tender axle 17 LT 15 cwt (18,030 kg) Adhesive weight 59 LT 14 cwt (60,660 kg) Loco weight 97 LT 15 cwt (99,320 kg) Tender weight 69 LT 8 cwt (70,510 kg) Total weight 167 LT 3 cwt (169,800 kg) Tender type JT (2-axle bogies) JT, JV permitted Fuel type Coal Fuel capacity 14 LT (14.2 t) Water cap 6,000 imp gal (27,300 l) Firebox type Round-top  • Firegrate area 63 sq ft (5.9 m2) Boiler: ​  • Model Watson Standard no. 3A  • Type Domeless  • Pitch 9 ft 3 in (2,819 mm)  • Diameter 6 ft 2 1⁄4 in (1,886 mm)  • Tube plates 19 ft 1⁄2 in (5,804 mm)  • Small tubes 136: 2 1⁄2 in (64 mm)  • Large tubes 36: 5 1⁄2 in (140 mm) Boiler pressure 210 psi (1,448 kPa) Safety valve Pop Heating surface 2,914 sq ft (270.7 m2)  • Tubes 2,682 sq ft (249.2 m2)  • Arch tubes 26 sq ft (2.4 m2)  • Firebox 206 sq ft (19.1 m2) Superheater: ​  • Heating area 592 sq ft (55.0 m2) Cylinders Two Cylinder size 24 in (610 mm) bore 28 in (711 mm) stroke Valve gear Rotary Cam Poppet Valve type Poppet Couplers AAR knuckle

Performance figures Tractive effort 35,280 lbf (156.9 kN) @ 75%

Career Operators South African Railways Class Class 16E Number in class 6 Numbers 854–859 Delivered 1935 First run 1935 Withdrawn 1972

The 2nd coupled axle had flangeless wheels

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.

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.

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.

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.

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).

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-nickel 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.