LMS Rebuilt Royal Scot Class

LMS Royal Scot Class
6127 The Old Contemptibles, as rebuilt in 1944
Type and origin Power type Steam Designer Sir William Stanier Rebuilder LMS Derby Works Rebuild date 1943–1955 Number rebuilt 70
Specifications Configuration: ​  • Whyte 4-6-0  • UIC 2′C h3 Gauge 4 ft 8+1⁄2 in (1,435 mm) standard gauge Leading dia. 3 ft 3+1⁄2 in (1.003 m) Driver dia. 6 ft 9 in (2.057 m) Length 63 ft 0+1⁄2 in (19.22 m) Loco weight 84.90 long tons (86.26 t; 95.09 short tons) Tender weight 54.65 long tons (55.53 t; 61.21 short tons) Water cap. 4,000 imp gal (18,000 L; 4,800 US gal) Tender cap. 9 long tons (9.1 t; 10 short tons) Boiler 2A Boiler pressure 250 psi (1.72 MPa) superheated Cylinders Three Cylinder size 18 in × 26 in (457 mm × 660 mm) Valve gear Walschaerts Valve type Piston valves
Performance figures Tractive effort 33,150 lbf (147.46 kN)
Career Operators London, Midland and Scottish Railway → British Railways Power class 6P; reclassified 7P in 1951 Numbers LMS: 6100–6169 BR: 46100–46169 Axle load class BR: Route Availability 9 Disposition Two preserved; remainder scrapped

The London, Midland and Scottish Railway (LMS) Rebuilt Royal Scot Class is a class of 4-6-0 steam locomotives. 70 members of this class were rebuilt by the LMS and its successor British Railways (BR) from LMS Royal Scot Class engines by the replacement of their life expired parallel boilers with a type 2A boiler over the period 1943–1955. (The class sometimes is numbered 71 as it included a prototype 1935 rebuild LMS (4)6170 British Legion, but sufficient technical differences existed which dictate that it is treated separately). They were the second class to be rebuilt with type-2 boilers, after the rebuilding of British Legion and the Jubilee Class.

LMS gave them the power classification 6P; this was later revised by BR to 7P.