South African Class 2 4-6-2

This article is about one of two different Natal Government Railways locomotive types to be designated "Class A". For the other NGR Class A locomotive, see South African Class 2C 4-6-2.

NGR Class A 4-6-2 1905
South African Class 2 4-6-2

NGR Class A no. 326, SAR Class 2 no. 763

Type and origin Power type Steam Designer Natal Government Railways (D.A. Hendrie) Builder North British Locomotive Company Serial number 16192-16193 Model NGR Hendrie A Build date 1904 Total produced 2

Specifications Configuration 4-6-2 (Pacific) Driver axle 2nd coupled axle Gauge 3 ft 6 in (1,067 mm) Cape gauge Leading dia Coupled dia 51 in (1,295 mm) Trailing dia 30 in (762 mm) Tender wheels 30 in (762 mm) Wheelbase  • Engine 27 ft 10 in (8,484 mm)  • Leading 6 ft (1,829 mm)  • Coupled 9 ft 4 in (2,845 mm)  • Tender 15 ft 6 in (4,724 mm)  • Tender bogie 4 ft 6 in (1,372 mm) Length:  • Over couplers Height 12 ft 6 in (3,810 mm) Frame type Plate Axle load  • Leading  • 1st coupled  • 2nd coupled  • 3rd coupled  • Trailing  • Tender bogie Bogie 1: Bogie 2:  • Tender axle Adhesive weight Loco weight Tender weight w/o Loco & tender weight w/o Tender type SH (2-axle bogies) SH, SK permitted Fuel type Coal Fuel capacity 6 LT (6.1 t) Water cap Boiler:  • Pitch 7 ft 3 in (2,210 mm)  • Diameter  • Tube plates  • Small tubes 246: 2 in (51 mm)  • Firebox type Belpaire Boiler pressure 180 psi (1,241 kPa) Safety valve Ramsbottom Firegrate area 28 sq ft (2.6 m2) Heating surface 2,231 sq ft (207.3 m2)  • Tubes 2,112 sq ft (196.2 m2)  • Firebox 119 sq ft (11.1 m2) Cylinders Two Cylinder size 19 in (483 mm) bore 24 in (610 mm) stroke Valve gear Stephenson Valve type Slide Couplers Bell link-and-pin

Performance figures Tractive effort 22,940 lbf (102.0 kN) @ 75%

Career Operators Natal Government Railways South African Railways Class NGR Class A SAR Class 2 Number in class 2 Numbers NGR 325-326 SAR 762-763 Nicknames Hendrie A Delivered 1905 First run 1905 Withdrawn 1936

The 2nd coupled axle had flangeless wheels

The South African Railways Class 2 4-6-2 of 1905 was a steam locomotive from the pre-Union era in the Natal Colony.

In 1905, the Natal Government Railways placed two Class A steam locomotives with a 4-6-2 Pacific type wheel arrangement in service. In 1912, when these locomotives were assimilated into the South African Railways, they were renumbered and designated Class 2.

Manufacturer

In 1904, orders were placed with the North British Locomotive Company (NBL) for two 4-6-2 Pacific type locomotives for the Natal Government Railways (NGR). They were designed by NGR Locomotive Superintendent D.A. Hendrie, for passenger traffic on those sections of the mainline, between Ladysmith and Charlestown, which did not have very severe gradients. When they were delivered and placed in service early in 1905, they were designated the NGR Class A, also commonly known as the Hendrie A, and numbered 325 and 326.

Characteristics

The boiler of this Class was noted for its free steaming qualities. The engines used saturated steam, had Stephenson valve gear and were built on plate frames. The cylinders were inclined 1 in 18 and were arranged outside the plate frames, while the balanced slide valves were arranged inside the frames. After these two engines, Hendrie adopted outside valves and Walschaerts valve gear on all his subsequent locomotive designs, for its greater accessibility.

File:D.A. Hendrie.jpg

D.A. Hendrie

The locomotives had Belpaire fireboxes with firebar rocking finger grates. To accommodate the wide and deep firebox, Hendrie made use of a bridle casting, along the same lines as the one which was first introduced by H.M. Beatty on his Cape Government Railways (CGR) 6th Class 2-6-2 of 1903, later the Class 6Y on the South African Railways (SAR).

With a bridle casting, the widening of the locomotive frame at the back end was accomplished by uniting the narrow front part of the frame and the wider rear part by the heavy steel casting. This method of widening the frames for the firebox continued on the SAR until 1927, when the general adoption of bar frames for mainline locomotives rendered it no longer necessary.

Service

Natal Government Railways

The two locomotives ran their first trials on 31 January and 3 March 1905 respectively. They were placed in service between Ladysmith and Charlestown, as intended, and were shedded at Charlestown. They worked the mail trains on this section for many years.

South African Railways

When the Union of South Africa was established on 31 May 1910, the three Colonial government railways (CGR, 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 two Pacifics were renumbered 762 and 763 and designated Class 2 on the SAR.

They were later transferred to the Witwatersrand for a short period, after which they worked on the Komatipoort-Waterval Boven section, until they were withdrawn by 1936.