South African Class 1A 4-8-0

This article is about one of several different Natal Government Railways locomotive types to be designated "Class B". For other NGR Class B locomotives, see Natal Government Railways Class B locomotives.

NGR Class B 4-8-0 1910
South African Class 1A 4-8-0

300px SAR Class 1A no. 1301, ex NGR Class B no. 25, Mason's Mill Loco, 6 July 1962

Type and origin Power type Steam Designer Natal Government Railways (D.A. Hendrie) Builder North British Locomotive Company Serial number 19051-19071 Model NGR Hendrie B Build date 1910 Total produced 21

Specifications Configuration 4-8-0 (Mastodon) Driver axle 2nd coupled axle Gauge 3 ft 6 in (1,067 mm) Cape gauge Leading dia Coupled dia 46 in (1,168 mm) Tender wheels 30 in (762 mm) Wheelbase  • Engine 22 ft 6 in (6,858 mm)  • Leading 6 ft (1,829 mm)  • Coupled 12 ft 9 in (3,886 mm)  • Tender 16 ft 6 in (5,029 mm)  • Tender bogie 4 ft 6 in (1,372 mm) Length:  • Over couplers 57 ft 10 in (17,628 mm) Height Frame type Plate Axle load  • Leading  • 1st coupled  • 2nd coupled  • 3rd coupled  • 4th coupled  • Tender bogie Bogie 1: Bogie 2:  • Tender axle Adhesive weight Loco weight Tender weight w/o Loco & tender weight w/o Tender type TJ (2-axle bogies) TJ, TL, TM permitted Fuel type Coal Fuel capacity 6 LT (6.1 t) Water cap Boiler:  • Pitch  • Diameter  • Tube plates 12 ft 1 in (3,683 mm)  • Small tubes 325: 2 in (51 mm)  • Firebox type Belpaire with combustion chamber Boiler pressure 190 psi (1,310 kPa) Safety valve Ramsbottom Firegrate area 34 sq ft (3.2 m2) 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 bore 24 in (610 mm) stroke Valve gear Walschaerts Valve type "D" slide valves Piston valves on no. 33 Couplers Bell link-and-pin AAR knuckle (1950s)

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Class NGR Class B SAR Class 1A Number in class 21 Numbers NGR 13-33 SAR 1289-1309 Delivered 1910 First run 1910 Withdrawn 1974

The leading coupled axle had flangeless wheels

The South African Railways Class 1A 4-8-0 of 1910 was a steam locomotive from the pre-Union era in the Natal Colony.

In 1910, the Natal Government Railways placed 21 improved Class B 4-8-0 Mastodon type tender locomotives in service. In 1912, when these locomotives were assimilated into the South African Railways, they were renumbered and classified as Class 1A.

Manufacturer

File:D.A. Hendrie.jpg

D.A. Hendrie

By 1909, more locomotives were required for goods operation on the lower sections of the Natal mainline and a further 21 locomotives of the Class B 4-8-0 Mastodon design were ordered by the Natal Government Railways (NGR). They were delivered and placed in service in 1910, built by the North British Locomotive Company, with Type TJ tenders and numbered in the range from 13 to 33. These locomotives were also officially designated Class B and, since they incorporated various improvements on the locomotives of 1904, they became commonly known as the Class Improved Hendrie B.

Characteristics

Like their predecessors, they had Belpaire fireboxes with combustion chambers and Walschaerts valve gear. While they were practically identical to the 1904 lcomotives in most respects, their boilers had been raised by , which raised the boiler pitch by 1 inch (25 millimetres) to and gave a better rake on the sides of the ash pan.

Like the 1904 Class B Hendrie B locomotives, all but one used slide valves. The exception was the last locomotive, no. 33, which was an experimental locomotive equipped with piston valves.

Hendrie's steam reverser

File:Class 1A 4-8-0 steam reverser.jpg

Hendrie's steam reverser

They were built with Hendrie’s steam reversers. The Hendrie steam reversing gear consisted of a diameter steam cylinder and a 5 inches (127 millimetres) diameter oil cylinder, arranged in line on a bracket which was fixed to the main engine frame on the driver's side. The cylinders had a common piston rod, which had a slot in the centre, between the cylinders. This slot accommodated a sliding crosshead, which engaged with an arm, fixed to the reversing shaft.

By means of a small lever, the driver could admit steam to either end of the steam cylinder, which would open a cataract valve, arranged on top of the oil cylinder, to allow oil to flow from either end of the oil cylinder to the other. A pointer in the cab would indicate the exact position of the reversing gear and, when the desired position was reached, bringing the hand lever to the central position would close the cataract valve and fix the gear in the forward or reverse position.

South African Railways

File:Class 1A 1293 (4-8-0).JPG

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When the Union of South Africa was established on 31 May 1910, the three Colonial government railways (Cape Government Railways, NGR and Central South African Railways) were united under a single administration to control and administer the railways, ports and harbours of the Union. Although the South African Railways and Harbours came into existence in 1910, the actual classification and renumbering of all the rolling stock of the three constituent railways required careful planning and was only implemented with effect from 1 January 1912.

In 1912, these locomotives were renumbered in the range from 1289 to 1309 and designated Class 1A on the South African Railways (SAR).

Service

When new, they were used to haul fast passenger and goods trains between Durban and Pietermaritzburg. In SAR service, they were also used on mainline workings out of Port Elizabeth. In later years, they were relegated to shunting, particularly working in Natal but also in Cape Town, Port Elizabeth, East London and in the Transvaal. None of them was reboilered with a Watson Standard boiler with a round-topped firebox.

In their last years, few Class 1 and Class 1A locomotives were still at work. As at April 1973, for example, there were still three working at Mason’s Mill in Pietermaritzburg and one in the Eastern Transvaal, two of them Class 1A. The last Class 1A locomotive was retired by the SAR in November 1974.

In industrial service, no. 1301 survived longer and was still in service in 1984, as Apex Mines no. 3 at Greenside.

Works numbers and renumbering

Their works numbers, numbering and SAR renumbering are listed in the table.

NGR Class B 4-8-0 of 1910
SAR Class 1A 4-8-0

Works no.	NGR no.	SAR no.
19051	13	1289
19052	14	1290
19053	15	1291
19054	16	1292
19055	17	1293
19056	18	1294
19057	19	1295
19058	20	1296
19059	21	1297
19060	22	1298
19061	23	1299
19062	24	1300
19063	25	1301
19064	26	1302
19065	27	1303
19066	28	1304
19067	29	1305
19068	30	1306
19069	31	1307
19070	32	1308
19071	33	1309

Illustration

The main picture shows a Class 1A locomotive with a modified Type TJ tender, while the following picture shows one with a Type TL tender, which was rebuilt from a Type TJ tender c. 1930.

• Class 1A no. 1300 & Type TL.jpg

  Class 1A no. 1300 with Type TL tender, c. 1930