GWR 5700 Class

Great Western Railway 5700 class

GWR 5700 Class no. 4612, as preserved on the Bodmin & Wenford Railway.

Type and origin Power type Steam Designer Charles Collett Builder GWR Swindon Works (613) Armstrong Whitworth (25) W. G. Bagnall (50) Beyer, Peacock & Co. (25) Kerr Stuart (25) North British Locomotive (100) Yorkshire Engine Co. (25) Order number See Build details below Build date 1929–1950 Total produced 863

Specifications Configuration 0-6-0PT UIC class C nt Gauge 4 ft 8 1⁄2 in (1,435 mm) standard gauge Driver dia. 4 ft 7 1⁄2 in (1.410 m) Minimum curve 5 chains (330 ft; 101 m) normal 4 1⁄2 chains (297 ft; 91 m) slow Wheelbase 15 ft 6 in (4.72 m) Length 31 ft 2 in (9.50 m) over buffers Width 8 ft 7 in (2.616 m) Height 12 ft 3 1⁄16 in (3.735 m) Frame type Type: Inside Length: 27 ft 6 in (8.38 m) Width: 8 ft 7 in (2.616 m) Axle load 16 long tons 15 cwt (37,500 lb or 17 t) (18.8 short tons) full Loco weight 47 long tons 10 cwt (106,400 lb or 48.3 t) (53.2 short tons) full Fuel type Coal Fuel capacity 3 long tons 6 cwt (7,400 lb or 3.4 t) (3.7 short tons) Water cap 1,200 imp gal (5,500 l; 1,400 US gal) Firebox:  • Firegrate area 15.3 sq ft (1.42 m2) Boiler Barrel: 10 ft 3 in (3.12 m) Outside diameter: 4 ft 5 in (1.35 m) & 4 ft 3 7⁄8 in (1.318 m) Pitch: 6 ft 11 3⁄4 in (2.127 m) Boiler pressure 200 lbf/in2 (1.38 MPa) Heating surface 1,178.0 sq ft (109.44 m2)  • Tubes 1,075.7 sq ft (99.94 m2)  • Firebox 102.3 sq ft (9.50 m2) Cylinders Two, inside Cylinder size 17.5 in × 24 in (444 mm × 610 mm) Valve gear Stephenson Valve type Slide valves Train heating steam Loco brake steam Train brakes vacuum Safety systems ATC

Performance figures Tractive effort 22,515 lbf (100.15 kN)

Career Operators GWR » BR Power class GWR: C BR: 3F Numbers See Numbering below Axle load class GWR: Blue until 1950, then Yellow Withdrawn 1956–1966 Preserved 16

The Great Western Railway (GWR) 5700 Class, or 57xx class, is a class of 0-6-0 pannier tank steam locomotive, built between 1929 and 1950. 863 were built, making them the most prolific class of the GWR, and one of the most numerous classes of British steam locomotive.

Although officially designated by GWR as "light goods and shunting engines", they were also used for passenger working on branch, suburban, and shorter mainline journeys.

They were distributed across most of the GWR network and, after nationalisation of the railways in 1948, across the British Railways Western Region, and also other regions.

The 5700s were not as glamorous as the GWR Castles and Kings, but became just as much of an icon of the GWR.

As a result of the 1955 Modernisation Plan, the 5700 Class was withdrawn from BR service between 1956 and 1966. Nineteen withdrawn locomotives were sold to London Transport and industry, of which ten were later preserved, along with six that were retrieved from scrapyards.

The GWR started designing and building 0-6-0 tank locomotives in 1860, and this continued into the BR era until 1956, with a total of 2,393 being built. The GWR also used 0-6-0 tank locomotives from other manufacturers' designs (from its subsidiary and absorbed railways' stock), and since 1898 it always had at least 1,000 tank locomotives in stock.

The early 0-6-0 tank engines were fitted with either saddle tanks (wrapped over the boiler) or side tanks (mounted at the side of the boiler and reaching down to the running platform). GWR first fitted pannier tanks (mounted on the side of the boiler but not reaching down to the running platform) in 1898 to nine 4-4-0 tank locomotives and, in 1901, to five 0-6-0T locomotives which were also fitted with Belpaire fireboxes. The shape of the Belpaire firebox gives a larger surface area which improves heat transfer and steam production, but their rectangular shape made them difficult to combine with saddle tanks. Locomotives fitted with pannier tanks have a lower centre of gravity than those with saddle tanks (enabling higher speeds on curves), and access for maintenance is easier than for those fitted with side tanks.