LB&SCR H1 class

LB&SCR H1 class
Official photograph of No.37 shortly after delivery in 1905.
Type and origin Power type Steam Designer D. E. Marsh Builder Kitson & Co. Build date 1905–1906 Total produced 5
Specifications Configuration: ​  • Whyte 4-4-2 Gauge 4 ft 8 1⁄2 in (1,435 mm) standard gauge Leading dia. 3 ft 6 in (1.067 m) Driver dia. 6 ft 7 1⁄2 in (2.019 m) Total weight 106 long tons 5 cwt (238,000 lb or 108 t) (119 short tons) Fuel type Coal Boiler pressure 200 psi (13.79 bar; 1.38 MPa) Cylinders Two, outside Cylinder size 18.5 in × 26 in (470 mm × 660 mm)
Performance figures Tractive effort 19,028 lbf (84.6 kN)
Career Class H1 Power class BR: 3P Withdrawn 1944–1951 Disposition All scrapped

The London, Brighton and South Coast Railway H1 class was a class of 4-4-2 steam locomotives for express passenger work. They were designed by D. E. Marsh and were built by Messrs Kitson & Co. in 1905 and 1906.

Prior to taking up office as the Locomotive Superintendent of the London, Brighton and South Coast Railway in 1905, Douglas Earle Marsh had worked for the Great Northern Railway at Doncaster Works. There he had been involved in the design of the Klondyke class designed by Henry Ivatt in 1897. There was an urgent need for new large express passenger locomotives for the LB&SCR and so he obtained a set of drawings from Doncaster, and made only detailed amendments before ordering them from the manufacturer. He did however increase the boiler pressure from 175 to 200 pounds per square inch (1.21 to 1.38 MPa).

The class soon proved to be successful working the London to Brighton express trains including the heavily loaded Pullman services the "Brighton Limited", and The Southern Belle, which the LB&SCR described as "the most luxurious train in the World".

In May 1920 L. B. Billinton wished to install the Schmidt superheater to improve the efficiency of the class, but was refused permission to do so by the Brighton Locomotive Committee. This modification was however carried out by Richard Maunsell of the Southern Railway during 1925–1926 after the "Grouping" of 1923.