South African Class 17 4-8-0TT

South African Class 17 4-8-0TT

SAR Class 17 no. 1432, circa 1930

Type and origin Power type Steam Designer Natal Government Railways (William Milne) Builder Dübs and Company South African Railways Serial number See table Model SAR Class 17 Build date 1926-1929 Total produced 21

Specifications Configuration 4-8-0TT (Mastodon) Driver axle 2nd coupled axle Gauge 3 ft 6 in (1,067 mm) Cape gauge Leading dia Coupled dia 39 in (991 mm) Tender wheels 34 in (864 mm) Wheelbase  • Engine 19 ft 9 in (6,020 mm)  • Leading 5 ft (1,524 mm)  • Coupled 11 ft (3,353 mm)  • Tender 16 ft 1 in (4,902 mm)  • Tender bogie 4 ft 7 in (1,397 mm) Length:  • Over couplers Height Axle load  • Leading  • 1st coupled  • 2nd coupled  • 3rd coupled  • 4th coupled  • Tender bogie Bogie 1: Bogie 2: Adhesive weight Loco weight Tender weight Loco & tender weight Tender type 2-axle bogies or 3-axle Fuel type Coal Fuel capacity 5 LT 10 cwt (5.6 t) Water cap engine Tender cap tender Boiler:  • Pitch 7 ft (2,134 mm)  • Diameter  • Tube plates  • Small tubes 187:  • Firebox type Belpaire Boiler pressure 160 psi (1,103 kPa) Safety valve Ramsbottom Firegrate area 24 sq ft (2.2 m2) Heating surface 992 sq ft (92.2 m2)  • Tubes 930 sq ft (86 m2)  • Firebox 62 sq ft (5.8 m2) Cylinders Two Cylinder size 17 in (432 mm) bore 21 in (533 mm) stroke Valve gear Stephenson Couplers Bell link-and-pin

Performance figures Tractive effort 18,670 lbf (83.0 kN) @ 75%

Career Operators South African Railways Class Class 17 Number in class 21 Numbers 1415–1435 Delivered 1926-1929 First run 1926 Withdrawn 1961

The leading coupled axle had flangeless wheels

The South African Railways Class 17 4-8-0TT of 1926 was a steam locomotive from the pre-Union era in the Natal Colony.

Between 1926 and 1929, to address a shortage of suitable shunting locomotives, the South African Railways rebuilt twenty-one Class A 4-8-2T Mountain type tank steam locomotives to Class 17 4-8-0TT Mastodon type tank-and-tender locomotives.

Manufacturers

The Natal Government Railways (NGR) Class D 4-8-2T Mountain type tank locomotive was designed by William Milne, the locomotive superintendent of the NGR from 1877 to 1896, and built by Dübs and Company. One hundred of these locomotives were delivered in ten batches by Dübs between 1888 and 1899, and in 1915 another two were built from spare parts by the South African Railways (SAR) in their Durban shops.

Belpaire firebox

Beginning in 1905, these NGR Class D locomotives, originally known on the NGR as the "Dübs A", were gradually reboilered and fitted with Belpaire fireboxes with wider firegrates. The unmodified locomotives were then designated NGR Class D1, while the modified locomotives with Belpaire fireboxes were designated Class D2. In SAR service, the NGR Class D1 and D2 were both designated Class A in 1912, while the modified locomotives were referred to as Class A Belpaire.

Rebuilding

NGR Class D1 no. 105, c. 1900

When a shortage of suitable shunting locomotives developed in the 1920s, as a result of increasing traffic throughout the country and particularly on the Witwaters­rand, the SAR modified twenty-one of the Class A Belpaire 4-8-2T Mountain type tank loco­mo­tives. The modifications were done between 1926 and 1929 and consisted of the removal of their trailing bissel bogies and coal bunkers, the shortening of their main frames and the addition of tenders to increase their coal and water capacity, thereby converting them to 4-8-0TT Mastodon type tank-and-tender locomotives.

Tenders from various scrapped locomotive types were used. The tender depicted in the main picture is a three-axle tender, while the official SAR locomotive diagram depicts a tender with four axles on two bogies. The bogie tenders which were used, were similar to those originally used with the Class 7E.

Service

These twenty-one rebuilt 4-8-2TT locomotives were reclassified to Class 17 and renumbered in the range from 1415 to 1435. They were employed as shunting engines around Durban and Port Elizabeth and were withdrawn from service by 1961, more than seventy years after the first one was built.

In November 1953, two of these locomotives, numbers 1423 and 1431, were purchased by the Zambezi Saw Mills Company, for use on their Livingstone-Mulobezi logging railway in Northern Rhodesia. They were scrapped between 1961 and 1963.

Works numbers and renumbering

Class A Belpaire rebuilt to Class 17

Class 17 No.	Year Built	NGR Class D2 No.	SAR Class A No.	Dübs Works No.
1415	1898	113	158	3556
1416	1897	108	154	3484
1417	1890	68	116	2611
1418	1899	134	190	3820
1419	1890	82	128	2625
1420	1890	75	122	2618
1421	1890	61	109	2604
1422	1895	89	135	3317
1423	1890	80	193	2626
1424	1898	120	166	3563
1425	1890	71	119	2614
1426	1895	90	136	3318
1427	1890	69	117	2612
1428	1890	70	118	2613
1429	1899	143	181	3829
1430	1899	141	191	3827
1431	1897	105	151	3481
1432	1898	112	157	3605
1433	1890	83	129	2623
1434	1897	101	147	3477
1435	1898	121	163	3564