LSWR S15 class

LSWR/SR S15 class[1]
S15 No. 833
Type and origin Power type Steam Designer Robert Urie, modified by Richard Maunsell Builder LSWR/SR Eastleigh Works Build date 1920–1936 Total produced 45
Specifications Configuration: ​  • Whyte 4-6-0  • UIC 2′C h2 Gauge 4 ft 8+1⁄2 in (1,435 mm) standard gauge Leading dia. 3 ft 7 in (1.092 m) Driver dia. 5 ft 7 in (1.702 m) Length 65 ft 6+3⁄4 in (19.98 m) Total weight Urie: 136 long tons 1 cwt (138.2 t; 152.4 short tons) Maunsell: 135 long tons 13 cwt (137.8 t; 151.9 short tons) Fuel type Coal Fuel capacity 5 long tons (5 t; 6 short tons) Water cap. 5,000 imp gal (23,000 L; 6,000 US gal) Boiler pressure Urie locomotives: 180 lbf/in2 (1.24 MPa); Saturated Boiler: 175 lbf/in2 (1.21 MPa); Maunsell locomotives: 200 lbf/in2 (1.38 MPa) Cylinders Two, outside Cylinder size Urie: 21 in × 28 in (533 mm × 711 mm); Maunsell: 20+1⁄2 in × 28 in (521 mm × 711 mm) Valve gear Walschaerts
Performance figures Tractive effort Urie: 28,200 lbf (125.4 kN); Maunsell: 29,860 lbf (132.8 kN)
Career Operators London and South Western Railway → Southern Railway → British Railways Class S15 Power class LSWR / SR: A BR : 6F Numbers LSWR: 496–515 SR: E496–E515, E823–E847 → 496–515, 823–847 BR: 30496–30515, 30823-30837 30838–30847 Nicknames "Goods Arthurs" Locale Southern Region Withdrawn 1962–1966 Disposition 6 preserved or extant, 1 cannibalised, remainder scrapped

The LSWR S15 class is a British 2-cylinder 4-6-0 freight steam locomotive designed by Robert W. Urie, based on his H15 class and N15 class locomotives. The class had a complex build history, spanning several years of construction from 1920 to 1936. The first examples were constructed for the London and South Western Railway (LSWR), where they hauled freight trains to the south coast ports and further west to Exeter, as well as occasional passenger work in conjunction with their larger-wheeled N15 class counterparts.^[2][3]

Following the Grouping of railway companies in 1923, the LSWR became part of the Southern Railway, and the Chief Mechanical Engineer (CME) of the newly formed company, Richard Maunsell, increased the S15 class strength to 45 locomotives. Maunsell incorporated several improvements, notably to the steam circuit and the locomotive's loading gauge, allowing it to operate on routes with height and width restrictions.^[3]

The new locomotives were built in three batches at Eastleigh, and were in service with the Southern Railway for 14 years. The locomotives continued in operation with the Southern Region of British Railways until 1966. Seven examples have been preserved for use on heritage railways, and are currently in varying states of repair. These locomotives were given the nickname "Goods Arthurs" due to their similar appearance to the N15 Class locomotives.^[4]