South African Class 16C 4-6-2

South African Class 16C & 16CR 4-6-2

Class 16C no. 825, as built, with Belpaire firebox

Type and origin ♠ Class 16C as built with a Belpaire firebox ♥ Class 16CR rebuilt with a Watson Standard boiler ʘ Larger 63 inch coupled wheels ♣ Steel firebox - ♦ Copper firebox Power type Steam Designer South African Railways (D.A. Hendrie) Builder North British Locomotive Company Serial number 21708-21717 (812-821) 22716-22735 (822-841) Model Class 16C Build date 1919-1922 Total produced 30

Specifications Configuration 4-6-2 (Pacific) Driver 2nd coupled axle Gauge 3 ft 6 in (1,067 mm) Cape gauge Leading dia. 30 in (762 mm) Coupled dia. ♠♥ 60 in (1,524 mm) ʘ 63 in (1,600 mm) Trailing dia. 33 in (838 mm) Tender wheels 34 in (864 mm) Wheelbase 55 ft 11 3⁄4 in (17,062 mm)  • Engine 29 ft 5 1⁄2 in (8,979 mm)  • Leading 6 ft 2 in (1,880 mm)  • Coupled 10 ft 9 in (3,277 mm)  • Tender 16 ft 9 in (5,105 mm)  • Tender bogie 4 ft 7 in (1,397 mm) Length: ​  • Over couplers 64 ft 4 1⁄8 in (19,612 mm) Height ♠ 12 ft 10 in (3,912 mm) ʘ 12 ft 11 1⁄2 in (3,950 mm) ♥ 12 ft 11 1⁄4 in (3,943 mm) Frame type Plate Axle load ♠♥ 17 LT 14 cwt (17,980 kg) ʘ 18 LT 3 cwt (18,440 kg)  • Leading ♠ʘ 16 LT 1 cwt (16,310 kg) ♥ 16 LT 12 cwt (16,870 kg)  • Coupled ♠ 17 LT 14 cwt (17,980 kg)  • 1st coupled ʘ 18 LT 1 cwt (18,340 kg) ♥ 17 LT 11 cwt (17,830 kg)  • 2nd coupled ʘ 18 LT 3 cwt (18,440 kg) ♠♥ 17 LT 14 cwt (17,980 kg)  • 3rd coupled ʘ 18 LT 1 cwt (18,340 kg) ♥ 17 LT 11 cwt (17,830 kg)  • Trailing ♠ʘ 13 LT 4 cwt (13,410 kg) ♥ 13 LT 7 cwt (13,560 kg)  • Tender bogie Bogie 1: 27 LT 10 cwt (27,940 kg) Bogie 2: 23 LT 11 cwt (23,930 kg)  • Tender axle 13 LT 15 cwt (13,970 kg) Adhesive weight ♠ 53 LT 2 cwt (53,950 kg) ʘ 54 LT 5 cwt (55,120 kg) ♥ 52 LT 16 cwt (53,650 kg) Loco weight ♠ 82 LT 7 cwt (83,670 kg) ʘ 83 LT 10 cwt (84,840 kg) ♥ 82 LT 15 cwt (84,080 kg) Tender weight 51 LT 1 cwt (51,870 kg) Total weight ♠ 133 LT 8 cwt (135,500 kg) ʘ 134 LT 11 cwt (136,700 kg) ♥ 133 LT 16 cwt (135,900 kg) Tender type MP1 (2-axle bogies) MP, MP1, MR, MS, MT, MT1, MT2, MX, MY, MY1 permitted Fuel type Coal Fuel capacity 10 LT (10.2 t) Water cap 4,250 imp gal (19,300 l) Firebox type ♠ Belpaire ♥ Round-top  • Firegrate area ♠♥ 37 sq ft (3.4 m2) Boiler: ​  • Model Watson Standard no. 2B  • Pitch ♠ 7 ft 9 in (2,362 mm) ʘ 7 ft 10 1⁄2 in (2,400 mm) ♥ 8 ft (2,438 mm)  • Diameter ♠ 5 ft 4 3⁄8 in (1,635 mm) ♥ 5 ft 7 1⁄2 in (1,714 mm)  • Tube plates ♠ 15 ft 10 1⁄2 in (4,839 mm) ♥♣ 18 ft 4 in (5,588 mm) ♥♦ 18 ft 3 5⁄8 in (5,578 mm)  • Small tubes ♠ 113: 2 1⁄4 in (57 mm) ♥ 87: 2 1⁄2 in (64 mm)  • Large tubes ♠ 21: 5 1⁄2 in (140 mm) ♥ 30: 5 1⁄2 in (140 mm) Boiler pressure ♠♥ 190 psi (1,310 kPa) ʘ 200 psi (1,379 kPa) Safety valve ♠ Ramsbottom - ♥ Pop Heating surface ♠ 1,712 sq ft (159.1 m2) ♥ 1,978 sq ft (183.8 m2)  • Tubes ♠ 1,534 sq ft (142.5 m2) ♥ 1,836 sq ft (170.6 m2)  • Firebox ♠ 178 sq ft (16.5 m2) ♥ 142 sq ft (13.2 m2) Superheater: ​  • Type Robinson  • Heating area ♠ 313 sq ft (29.1 m2) ♥ 472 sq ft (43.9 m2) Cylinders Two Cylinder size 22 in (559 mm) bore 26 in (660 mm) stroke Valve gear Walschaerts Valve type Piston Couplers Johnston link-and-pin AAR knuckle (1930s)

Performance figures Tractive effort ♠♥ 29,890 lbf (133.0 kN) @ 75% ʘ 29,960 lbf (133.3 kN) @ 75%

Career Operators South African Railways Class Class 16C & 16CR Number in class 30 Numbers 812-841 Delivered 1919-1922 First run 1919 Withdrawn 1976

As built, the 2nd coupled axle had flangeless wheels

The South African Railways Class 16C 4-6-2 of 1919 was a steam locomotive.

During 1919, the South African Railways placed ten Class 16C steam locomotives with a 4-6-2 Pacific type wheel arrangement in mainline passenger service. Another twenty entered service in 1922. Unlike the earlier Classes 16 and 16B, these locomotives had combustion chambers.

The Class 16C 4-6-2 Pacific type locomotive was designed by D.A. Hendrie, Chief Mechanical Engineer (CME) of the South African Railways (SAR), and built by the North British Locomotive Company (NBL) in Glasgow, Scotland. Ten locomotives were delivered in 1919, numbered in the range from 812 to 821. A second order followed in 1921 for another twenty locomotives which were numbered in the range from 822 to 841 when they were delivered in 1922.

They were identical to the predecessor Classes 16 and 16B in most respects, except that Hendrie had added a combustion chamber to the boiler, similar to that of the Class 15A. This reduced the distance between tube plates from 18 feet 3 inches (5,563 millimetres) to 15 feet 10 ¹⁄₂ inches (4,839 millimetres). The presence of the combustion chamber was visible externally as an extension of the Belpaire firebox hump.

The engines were equipped with Lambert sanding gear, which was a "wet" system whereby a mixture of water and sand was delivered to the rails. Under ideal conditions with fine-grained sand, results were fairly good, but maintenance problems and cost led to reversion to gravity sanding on later engines.

The boilers were fitted with the Robinson type superheater, the first time this type was used on a Hendrie engine. The Robinson header was constructed with compartments, alternately for saturated and super­heated steam. There were eight inlet and outlet ends of superheater elements expanded into the bottom wall of each compart­ment, with the exception of those compartments at each end, into which only three element ends were expanded. Three cover plates were bolted to the front of the header to allow access to the respective compartments, for expanding the element tubes in position or forcing them out when necessary.

During 1937, the Class 16C engines were fitted with Stone-Deuta speed indicators. As built, the second coupled axle had flangeless wheels, but these were later retyred with flanges to obtain better distribution of tyre flange wear and improved running.