LSWR L11 Class

The LSWR L11 Class, nicknamed the Large Hoppers, was a series of 40 inside-cylinder 4-4-0 express and secondary passenger locomotives designed by Dugald Drummond and built at Nine Elms Works from 1903, a development of the K10 Class with marginally larger dimensions and slightly higher boiler pressure intended for somewhat more demanding express passenger work across the LSWR's main lines. The Large Hopper designation distinguished the L11 from the slightly smaller K10 Small Hoppers, both classes sharing the characteristic double-dome boiler that gave all Drummond's LSWR double-dome classes their Hopper family name.

The L11 used 6 ft 0 in coupled wheels — larger than the K10's 5 ft 7 in but still smaller than the T9 express engines' 6 ft 7 in — placing it firmly in the secondary express and semi-fast passenger niche between the outer-suburban K10 and the front-line T9. Drummond designed the L11 for the LSWR's semi-fast passenger services: the Waterloo–Basingstoke–Salisbury–Exeter route stopping trains, the Portsmouth and Bournemouth semi-fasts, and the cross-country services that connected the LSWR's main lines with the branch network across Hampshire, Wiltshire, and Dorset.

In service the L11 Class gave more capable performance than the K10 on the steeper gradients and longer distances of the semi-fast routes, but like much of Drummond's LSWR locomotive output it was competent rather than brilliant. The class worked SR secondary passenger duties after the 1923 Grouping and was progressively displaced by more modern types through the 1930s and early 1940s. None was preserved.