GNR Class J23

GNR Class J23
LNER Classes J50 & J51

J50/3 No. 68973 0-6-0T at Doncaster Locomotive Depot, fresh from repair at Doncaster Works

Type and origin Power type Steam Designer Nigel Gresley Builder Doncaster Works Gorton Works Build date 1913–1939 Total produced 102

Specifications Configuration: ​  • Whyte 0-6-0T  • UIC C Gauge 4 ft 8 1⁄2 in (1,435 mm) standard gauge Driver dia. 56 in (1.422 m) Loco weight J50/1: 56.3 long tons (57.2 t; 63.1 short tons) J50/2: 57 long tons (58 t; 64 short tons) J50/3 & J0/4: 58.15 long tons (59.08 t; 65.13 short tons) Fuel type Coal Boiler pressure 175 psi (1.21 MPa) Cylinders Two, inside Cylinder size 18 1⁄2 in × 26 in (470 mm × 660 mm)

Performance figures Tractive effort 23,636 lbf (105.14 kN)

Career Operators London and North Eastern Railway British Railways Class GNR: J23; LNER: J50, J51 Power class BR: 4F Number in class J50/1: 10 J50/2: 40 J50/3: 38 J50/4: 13 Axle load class Route Availability 6 Disposition All original locomotives scrapped, 68905 replica currently planned to be built by The J50 Loco Group. But as of November 2015, no progress has been made

The Great Northern Railway Class J23 was a class of 0-6-0T steam locomotive. They had long side tanks that came to the front of the smokebox, which sloped forwards to improve visibility and had a recess cut in to aid maintenance. Forty were built by the Great Northern Railway (GNR) between 1913 and 1922, with a further 62 being added by the London and North Eastern Railway (LNER) between 1924 and 1939. There are plans to build a new J50/2 as of April 2013.

For shunting and local goods work, the Great Northern Railway (GNR) had traditionally used saddle-tank engines of the 0-6-0 wheel arrangement; the last of these, of GNR Class J13, having been built in 1909 to the designs of H.A. Ivatt, the GNR Locomotive Superintendent.

Nigel Gresley succeeded Ivatt in 1911, and soon identified a need for engines to work the short-haul coal traffic in the West Riding of Yorkshire; the nature of which required that the locomotives also be suitable for shunting. He designed a new class of 0-6-0 tank engine, using side tanks instead of saddle tanks. Gresley had recently begun the rebuilding of the GNR Class L1 0-8-2T locomotives with larger boilers, 4 feet 8 inches (1.42 m) in diameter, which left a number of 4-foot-2-inch (1.27 m) diameter boilers spare. Thirty of these were used in the construction of the new goods tank engines between 1913 and 1919; when ten more were built in 1922, these again used secondhand boilers, but 4 feet 5 inches (1.35 m) in diameter. On the GNR, both varieties were classified J23, but the LNER divided them into J51 with smaller boilers, and J50 with larger boilers. The LNER continued the construction of Class J50, building a further 62 up to 1939, only the first ten of which were given secondhand boilers. Class J51 were rebuilt to class J50 between 1929 and 1935.

Each of the two main classes exhibited variations: locomotive brakes could be operated by vacuum or steam pressure; the driving position could be on the right- or the left-hand side of the cab; and there were three sizes of coal bunker. These variations were recognised by class subdivisions: