Midland Railway 483 Class

The Midland Railway 483 Class 4-4-0 was a class of steam locomotive designed by Samuel W. Johnson for passenger work on the Midland Railway. This design formed the basis for the later LMS Class 2P 4-4-0. The London, Midland and Scottish Railway (LMS) seems to have inherited three batches of these locomotives and some of them passed into British Railways (BR) ownership in 1948.

Midland Railway 483 Class
Rebuilt Midland Johnson 2P 4-4-0 No. 40542 at Chesterfield 1959
Type and origin
Power typeSteam
DesignerSamuel W. Johnson
Build dateMidland locos built 1882-1901
S&DJ locos built 1914-1921
Specifications
Configuration:
​
 • Whyte4-4-0
Gauge4 ft 8 1⁄2 in (1,435 mm) standard gauge
Driver dia.Original, 6 ft 6.5 in (1.994 m)
Rebuilt, 7 ft 0.5 in (2.146 m)
Loco weight53 tons 7 cwt
Fuel typeCoal
Boiler pressure160 psi
CylindersTwo inside
Cylinder sizeOriginal, 18 in × 26 in (460 mm × 660 mm)
Rebuilt, 20.5 in × 26 in (520 mm × 660 mm)
Performance figures
Tractive effortOriginal, 15,960 lb
Rebuilt, 17,585 lb
Career
Power classLMS 2P

Numbering
  • BR numbers 40332-40397 (17 locomotives) originally built 1882-1891, some rebuilt from 1910 onwards
  • BR numbers 40400-40562 (143 locomotives) originally built 1891-1901, all rebuilt between 1912 and 1923
  • BR numbers 40322-40326 (5 locomotives) built for Somerset and Dorset Joint Railway 1914-1921 and taken into LMS stock in 1930

Note: two of the above number series contain gaps so the totals do not tally.

Rebuilding

On rebuilding, the Stephenson valve gear was retained but the following changes were made:

  • 18 in × 26 in (460 mm × 660 mm) cylinders with slide valves were replaced by 20.5 in × 26 in (520 mm × 660 mm) cylinders with piston valves
  • 6 ft 6.5 in (1.994 m) driving wheels were replaced by 7 ft 0.5 in (2.146 m) driving wheels
  • a superheater was fitted

References
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