South African Class 1 4-8-0

NGR Class B 4-8-0 1904
South African Class 1 4-8-0

SAR Class 1 no. 1245, ex NGR Class B no. 275

Type and origin Power type Steam Designer Natal Government Railways (D.A. Hendrie) Builder North British Locomotive Company Serial number 16370-16419 Model NGR Class B Build date 1904 Total produced 50 Rebuilder Natal Government Railways Rebuild date 1906 Number rebuilt 6 to Class B 4-8-2 (Mountain)

Specifications Configuration 4-8-0 (Mastodon) Driver 2nd coupled axle Gauge 3 ft 6 in (1,067 mm) Cape gauge Leading dia. 28 1⁄2 in (724 mm) Coupled dia. 45 1⁄2 in (1,156 mm) Tender wheels 30 in (762 mm) Wheelbase 49 ft 5⁄8 in (14,951 mm)  • Engine 22 ft 6 in (6,858 mm)  • Leading 6 ft (1,829 mm)  • Coupled 12 ft 9 in (3,886 mm)  • Tender 15 ft 6 in (4,724 mm)  • Tender bogie 4 ft 6 in (1,372 mm) Length: ​  • Over couplers 56 ft 4 7⁄8 in (17,193 mm) Height 12 ft 6 1⁄4 in (3,816 mm) Frame type Plate Axle load 14 LT 14 cwt (14,940 kg)  • Leading 14 LT 2 cwt (14,330 kg)  • 1st coupled 13 LT 9 cwt (13,670 kg)  • 2nd coupled 14 LT 14 cwt (14,940 kg)  • 3rd coupled 13 LT 18 cwt (14,120 kg)  • 4th coupled 13 LT 18 cwt (14,120 kg)  • Tender bogie Bogie 1: 18 LT 18 cwt (19,200 kg) Bogie 2: 19 LT 1 cwt (19,360 kg)  • Tender axle 9 LT 10 cwt 2 qtr (9,678 kg) Adhesive weight 55 LT 19 cwt (56,850 kg) Loco weight 70 LT 11 cwt (71,680 kg) Tender weight 37 LT 19 cwt (38,560 kg) Total weight 108 LT 10 cwt (110,200 kg) Tender type SH (2-axle bogies) SH, SK permitted Fuel type Coal Fuel capacity 6 LT (6.1 t) Water cap 3,225 imp gal (14,700 l) Firebox type Belpaire with combustion chamber  • Firegrate area 34 sq ft (3.2 m2) Boiler: ​  • Pitch 7 ft 3 1⁄4 in (2,216 mm)  • Diameter 5 ft 4 3⁄4 in (1,645 mm)  • Tube plates 12 ft 1 in (3,683 mm)  • Small tubes 325: 2 in (51 mm) Boiler pressure 190 psi (1,310 kPa) Safety valve Ramsbottom Heating surface 2,188 sq ft (203.3 m2)  • Tubes 2,056 sq ft (191.0 m2)  • Firebox 132 sq ft (12.3 m2) Cylinders Two Cylinder size 20 1⁄2 in (521 mm) bore 24 in (610 mm) stroke Valve gear Walschaerts Valve type Balanced slide Couplers Johnston link-and-pin AAR knuckle (1930s)

Performance figures Tractive effort 31,240 lbf (139.0 kN) @ 75%

Career Operators Natal Government Railways South African Railways Class NGR Class B SAR Class 1 Number in class 44 Numbers NGR 275-318 SAR 1245-1288 Nicknames Hendrie B Delivered 1904 First run 1904 Withdrawn 1975

The leading coupled axle had flangeless wheels

The South African Railways Class 1 4-8-0 of 1904 was a steam locomotive from the pre-Union era in the Colony of Natal.

In 1904, the Natal Government Railways placed fifty Class B 4-8-0 Mastodon type steam locomotives in service. Six of them were modified to a 4-8-2 Mountain type wheel arrangement in 1906. In 1912, when the remaining 44 4-8-0 locomotives were assimilated into the South African Railways, they were renumbered and designated Class 1.

Because of the limited coal and water range of the existing fleet of Natal Government Railways (NGR) tank locomotives as well as the necessity to double- and even triple-head over the worst sections of the mainline, NGR Locomotive Superintendent D.A. Hendrie was tasked to produce a locomotive of greater power and capable of longer distances without refuelling or rewatering to work the mainline’s steep 1 in 30 (3⅓%) gradients.

His resulting Class B achieved this, being more powerful and with a longer range. When the designs were completed, Hendrie proposed that only five locomotives should be ordered so that they may first be thoroughly tested in service before ordering more. The designs, however, were so well received that the NGR placed an immediate order for fifty locomotives with the North British Locomotive Company (NBL).

It does appear as though there was a fair degree of urgency to obtain these locomotives, evidenced on the one hand by the rush to place a large order for an untested locomotive and on the other hand by the fact that construction was accelerated by dividing it equally between NBL’s Hyde Park and Queens Park works. The NGR’s faith in Hendrie’s ability turned out to be well justified, however, considering the fact that some of these locomotives remained in service for over seventy years.

Delivered in 1904, the Class B 4-8-0 Mastodon type was the first tender locomotive to be placed in service by the NGR apart from the single home-built 4-6-2TT engine Havelock of 1888. Fifty were built, those numbered in the range from 275 to 299 at the NBL Hyde Park works and those numbered in the range from 300 to 324 at the NBL Queens Park works.