The LSWR/SR H15 class was a class of 2-cylinder 4-6-0 steam locomotives designed by Robert Urie for mixed-traffic duties on the LSWR. Further batches were constructed by Richard Maunsell for the Southern Railway after 1923. They were given the nickname of "Junior King Arthur" due to the size of their driving wheels, with those on the S15 and their N15 counterparts being and diameters respectively.
Construction history
The H15 class represented Robert Urie's first design for the LSWR. It was created in response to a desperate lack of adequate locomotives in service on the LSWR that could be utilised for heavy freight duties. Reliability was also an issue, with ageing locomotive designs taking their toll on the LSWR's resources.
Ten locomotives (numbers 482–491) were built new by Eastleigh Works with boilers. They appeared in January to July 1914. Urie was a proponent of superheating, so in order to gain experience and data on performance and fuel economy, four of the locomotives (482–485) were fitted with Schmidt superheaters, four (486–489) with Robinson superheaters, and two (490–491) were built as saturated locomotives. The last two had a lower weight than the first eight.
While the data gained from this small experiment showed the benefits of superheating, neither design of superheater was deemed suitable by Urie, so he designed and patented his own: the Eastleigh superheater,
An additional locomotive was a rebuild of the 1905 E14 class No. 335 undertaken in December 1914. The locomotive had been scheduled for major modifications by Urie's predecessor Dugald Drummond in the light of poor operational performance.
However, improvements were made to the overall design whilst the locomotive was under production at Eastleigh Works. The earlier class members mounted a lower running plate that was raised above the cylinders for clearance.
- On 8 February 1956, locomotive No. 30477 was derailed in an accident near .
Livery and numbering
LSWR and Southern
Livery was initially LSWR Drummond Lined Passenger Green livery, this being complemented by purple-brown edging and double yellow lining. The initials 'LSWR' were located on the tender, and the number was placed on the cabside.
The first Southern livery, as displayed by the 1924 batch, continued that of the LSWR, though with the number displayed on the tender. However, from 1925, a darker Olive-type green was substituted, and the entire class was so outshopped. Wheels were green with black tyres. Primrose Yellow 'Southern' and locomotive number transfers were placed on the tender tank.
The class was numbered according to the BR Standard Numbering System, given the series 30482–30491; 30521–30524; 30330–30334 (F13 rebuilds) and finally 30473–30478.