South African Class NG7 2-6-0

CGR Baldwin 2-6-0
South African Class NG7 2-6-0

Baldwin works photograph, c. 1902

Type and origin Power type Steam Designer Baldwin Locomotive Works Builder Baldwin Locomotive Works Serial number 19456, 19649, 19650, 36375 Build date 1901-1911 Total produced 4

Specifications Configuration: ​  • Whyte 2-6-0 (Mogul)  • UIC 1'Cn2 Driver 2nd coupled axle Gauge 2 ft (610 mm) narrow Leading dia. 22 in (559 mm) Coupled dia. 33 in (838 mm) Tender wheels 22 in (559 mm) Wheelbase 36 ft 5 in (11,100 mm)  • Engine 12 ft 10 in (3,912 mm)  • Coupled 7 ft (2,134 mm)  • Tender 13 ft 7 in (4,140 mm)  • Tender bogie 4 ft 1 in (1,245 mm) Wheel spacing (Asymmetrical) 1-2: 4 ft (1,219 mm) 2-3: 3 ft (914 mm) Length: ​  • Over couplers 43 ft 9 3⁄4 in (13,354 mm) Height 10 ft 4 3⁄4 in (3,169 mm) Frame type Bar Axle load:  • Leading 2 LT 4 cwt 2 qtr (2,261 kg)  • Coupled 5 LT 15 cwt 2 qtr (5,868 kg)  • Tender bogie Bogie 1: 10 LT 10 cwt 2 qtr (10,690 kg) Bogie 2: 10 LT 6 cwt (10,470 kg) Adhesive weight 17 LT 6 cwt 2 qtr (17,600 kg) Loco weight 19 LT 11 cwt (19,860 kg) Tender weight 20 LT 16 cwt 2 qtr (21,160 kg) Total weight 40 LT 7 cwt 2 qtr (41,020 kg) Tender type 2-axle bogies Fuel type Coal Fuel capacity 5 LT (5.1 t) Water cap 1,500 imp gal (6,820 l) Firebox type Round-top  • Firegrate area 0.71 m2 (7.6 sq ft) Boiler: ​  • Pitch 4 ft 8 3⁄8 in (1,432 mm)  • Diameter 3 ft 2 1⁄8 in (968 mm) Boiler pressure 180 psi (1,241 kPa) Safety valve Ramsbottom Heating surface 39.14 m2 (421.3 sq ft)  • Tubes 35.39 m2 (380.9 sq ft)  • Firebox 3.75 m2 (40.4 sq ft) Cylinders Two Cylinder size 11 3⁄4 in (298 mm) bore 16 in (406 mm) stroke Valve gear Stephenson Couplers Bell-and-hook

Performance figures Tractive effort 9,036 lbf (40.19 kN) @ 75%

Career Operators Cape Government Railways South African Railways Class Class NG7 Number in class 4 Numbers CGR 1-3, NG4 SAR NG22-NG24, NG35 Delivered 1902-1911 First run 1902 Withdrawn 1926

The 2nd coupled axle had flangeless wheels

The South African Railways Class NG7 2-6-0 of 1902 was a narrow gauge steam locomotive from the pre-Union era in the Cape of Good Hope.

In 1902, the Cape Government Railways placed three steam locomotives with a 2-6-0 Mogul type wheel arrangement in service on the Hopefield narrow gauge branch line which was being constructed from Kalbaskraal. A fourth locomotive was ordered in 1911.

In 1912, when these locomotives were assimilated into the South African Railways, they were renumbered with an "NG" prefix to their numbers. When a system of grouping narrow gauge locomotives into classes was eventually introduced somewhere between 1928 and 1930, they were to be classified as Class NG7, but had already been withdrawn from service and were eventually sold in 1930.

By 1900, the Cape of Good Hope Government began to consider the construction of 2 feet (610 millimetres) narrow gauge railways. The construction of two railways of this gauge, one from Kalbaskraal to Hopefield and another from Port Elizabeth to Avontuur, was sanctioned by the Cape Parliament in 1901. Even though the 2 feet 6 inches (762 millimetres) narrow gauge Namaqualand Railway had been in existence and successfully worked since 1869, the still narrower gauge 46-mile long (74-kilometre) Hopefield line was regarded by many as the pioneer railway of the narrow gauge at the Cape. Its working capacity and attendant advantages and disadvantages were therefore watched with interest throughout the Colony.

The Cape Government Railways (CGR) ordered three narrow gauge tender locomotives with a 2-6-0 Mogul type wheel arrangement from Baldwin Locomotive Works in 1901. They were numbered 1 to 3 when they were delivered in 1902 and were erected at the Salt River shops. A fourth locomotive, identical to the first three, was ordered from the same manufacturer in 1911 and became CGR no. NG4 upon delivery in that same year.

The locomotives were of a standard type which was being used on the narrow gauge railroads of Maine in the United States of America. They had bar frames and used Stephenson valve gear. The drivers, the middle wheelset of the coupled wheels, were flangeless to enable the engine to negotiate sharp curves.