sentences:  In order to facilitate the speedy overhaul of these locomotives in the confined spaces of Nine Elms, spare boilers were constructed.Coupled to a short wheelbase and guiding bogies, the locomotive was relatively manoeuvrable on tight curves, a feature that was to ensure the survival of some of the class later on.Upon the appointment of Dugald Drummond as Superintendent of the LSWR after Adams' departure, the class was modified slightly, with the application of his lipped chimney in place of the stovepipe version that the locomotives were equipped with when built.