Immediately following the [D2s and D3s] came a set of ten engines of similar type and dimensions, except for the fact that they had only a single pair of leading wheels instead of a bogie, and heavy outside plate frames of the Stirling pattern. The leading wheels were 4-ft. 1 1/2-in. in diameter and placed in advance of the driving wheels to the extent of 9-ft. 8-in., the total wheel-base being 17-ft. 11-in. The overhang of the frames was 3-ft. at the leading end and 3-ft. 11-in. at the trailing end. It will be noted from the accompanying illustration, Fig. 89, that the springs of the leading wheels were placed above the running plate, a position which renders them easier of access for inspection and repairs, though perhaps less neat than Mr. Stirling’s system of concealing them between the frames.
In the same way the removal of the sandboxes from the front of the driving-wheel splashers to a situation below the running plate allows much-desired facilities for getting at the motion. The boilers of these six-wheeled engines were identical in every respect with that of No. 400, already described. In full working order the engines weighed a total of 41 tons 10 cwt., distributed as follows: leading wheels 13 tons, driving wheels 15 tons, trailing wheels 13 tons 10 cwt. and the new standard tender was supplied, weighing 38 tons 6 cwt. when fully loaded. The numbers of these locomotives are given below: —
|Date||Doncaster Nos.||Engine Nos.|
It should be noted that the first three of these engines were built with a plain black beading round the driving splashers, while Nos. 1064- 1070 had the outer edge finished off with a brass rim.