L&YR Class 21

L&YR Class 21
L&YR 'Pug' 0-4-0ST at work in Goole Docks 1954
Type and origin Power type Steam Designer John Aspinall Builder Vulcan Foundry (3) Horwich Works (57) Order number Horwich Lots 10, 20, 26, 46, 52, 65 Serial number VF: 1176–1178 H: 811–20; 921–30, 1092–1111 Build date 1886, (3) 1891–1910 (57) Total produced 60
Specifications Configuration: ​  • Whyte 0-4-0ST  • UIC B n2t Gauge 4 ft 8 1⁄2 in (1,435 mm) standard gauge Driver dia. 3 ft 0 in (0.914 m) Wheelbase Vulcan: 6 ft 0 in (1.829 m) Horwich: 5 ft 9 in (1.753 m) Loco weight 21.25 long tons (21.59 t; 23.80 short tons) Fuel type Coal Boiler pressure Vulcan: 140 lbf/in2 (0.97 MPa); Horwich: 160 lbf/in2 (1.10 MPa) Heating surface 475.75 sq ft (44.199 m2) Cylinders Two, outside Cylinder size 13 in × 18 in (330 mm × 457 mm)
Performance figures Tractive effort 10,060–11,492 lbf (44.7–51.1 kN)
Career Operators Lancashire and Yorkshire Railway → London, Midland and Scottish Railway → British Railways Class L&YR: 21 Power class LMS: 0F Number in class 1 January 1923: 58; 1 January 1948: 23 Numbers LMS: 11200–11257 Retired 1910–1963 Disposition Two preserved, remainder scrapped

The L&YR Class 21 is a class of small 0-4-0ST steam locomotive built by the Lancashire and Yorkshire Railway for shunting duties. They were nicknamed Pugs.

The class originates in the purchase of three saddle tank locomotives ordered from Vulcan Foundry in 1886. They were fitted with an 8-foot-10-inch (2.69 m) long, 3-foot-0-inch (914 mm) diameter boiler pressed to 140 lbf/in² (965 kPa) powering two outside 13-by-18-inch (330 mm × 457 mm) cylinders connected to 3-foot-0-inch (914 mm) driving wheels. The wheelbase was 6 ft 0 in (1.83 m) and the total heating surface of the saturated boiler was 475.75 sq ft (44.20 m²).

J. A. F. Aspinall then ordered more locomotives of a modified design: the wheelbase was shortened to 5 ft 9 in (1.75 m), the tank was extended over the smokebox, the cab was enlarged, and the boiler pressure raised to 160 lbf/in² (1,103 kPa). Seventeen of this modified design were ordered from Horwich Works in three batches; Aspinall's successor Henry Hoy order another batch of 10; and Hoy's successor George Hughes ordered 30 more in two batches.

The last locomotive was delivered in July 1910, four months before the first retirement; 917 and 918 were withdrawn in November that year, but were not scrapped until November 1912.

The London, Midland and Scottish Railway (LMS) gave the locomotives the power classification 0F. In total sixty were made between 1886 and 1910. They were built for use in sharply curved sidings for shunting duties. The Pugs were allocated by the L&YR for operation in the industrial areas and docks of Fleetwood, Goole, Liverpool and Salford. In later times they became more widely dispersed, reaching places such as Bristol, Bangor, Crewe, Derby, Widnes, York and Swansea. When the LMS was merged into British Railways on 1 January 1948, 23 'Pugs' remained in service; BR added 40,000 to their fleet numbers.