 The locomotive was designed to carry 4 tons (4.06 tonnes) of coal and of water, and the coal bunker was covered by a tarpaulin to prevent water ingress into the fireman's cab.Entry into the locomotive was by way of ladders leading up to sliding doors, although, due to the bogie design, the climb into the fireman's cab necessitated clambering over the oilbath casing.Construction of the first five Leader locomotives began at the Southern Railway's Brighton railway works in July 1947.