LB&SCR I1 class
|LB&SCR I1 class|
|I1 class with modified chimney|
|Designer||D. E. Marsh|
|Gauge||4 ft 8 1⁄2 in (1,435 mm)|
|Driver diameter||5 ft 6 in (1.676 m)|
|Locomotive weight||66 long tons 10 cwt (149,000 lb or 67.6 t)|
|Water capacity||1,839 imp gal (8,360 l; 2,209 US gal) or 1,924 imp gal (8,750 l; 2,311 US gal)|
|Boiler pressure||170 psi (1.17 MPa)|
|Cylinder size||17.5 in × 26 in (445 mm × 660 mm)|
|Tractive effort||17,430 lbf (77.5 kN)|
This class was intended to haul secondary passenger trains, especially in the south London suburbs, and twenty locomotives were constructed by Brighton works between June 1906 and December 1907. The locomotives proved to be reliable but with disappointing performance in their original form, being poor steamers, but all of them passed to the Southern Railway in 1923.
I1X class 
Between 1925 and 1932 they were rebuilt by Richard Maunsell with spare boilers left over after the reuilding of the B4 and I3 classes. The rebuilt engines were designated I1x class, and these new larger boilders greatly improved their performance.
Two worn-out members of the class were withdrawn by the Southern Railway in 1944 and 1946 respectively, but the remainder survived into British Railways (BR) ownership in 1948, although all had been withdrawn by July 1951 and none have been preserved.
The first ten were numbered 595-604 and the second ten were numbered 1-10. The Southern Railway initially added a "B" prefix to these numbers and later renumbered them 2595-2604 and 2001-2010. BR added 30000 to the numbers but it is believed that only 32005 actually carried its number.
- Bradley 1974, p. 80.
- Bradley, D.L. (September 1974). The locomotives of the London Brighton and South Coast Railway, Part 3. London: RCTS.
- Dendy Marshall, C. F., History of the Southern Railway, Ian Allan 1988, page 270, ISBN 0-7110-0059-X