18 Series (F2)

Doncaster No. 1 engine was, as already mentioned, delivered on the rails at the latter end of 1867, and was fittingly enough the pioneer of a new type. It was specially designed by Mr. Stirling for working “mixed” traffic, ranging from heavy excursion to fast goods work, and for this the class has proved to be of such great utility that 153 locomotives of this type were eventually put to work.

Engines of this type run most of the fast passenger train services in the West Riding division of the line. As can be seen from the accompanying illustration, which shows the first of the class, these “mixed” engines ran on six wheels, of which the leading and driving pairs were coupled, while a small pair of independent wheels under the cab bore the weight of the trailing end. Fig. 37, however, represents only the first three of the series in actual details, these being the three engines built at Doncaster in 1867.

It will be noted that the square-sided cab with a circular window was the trial pattern first adopted by Mr. Stirling, which subsequently was replaced by the more familiar design already shown in the preceding figure. No. 18 and the two immediately following were distinguished from later editions by having only one large opening in each splasher, instead of two of the type shown in Fig. 36, and also by having a black beading round the splasher instead of the one of polished brass subsequently adopted.

The leading dimensions of the first engines of this new class were : cylinders 17-in. in diameter with a 24-in. stroke; diameter of coupled wheels 5-ft. 7-in., and of trailing wheels 3-ft. 7-in.; wheel-base: leading to driving axle 7-ft. 3-in., driving to trailing axle 7-ft. 11-in., total 15-ft. 2-in.; overhang of frame at leading end 4-ft. 10 1/2-in., and at trailing end 2-ft. 7-in. ; boiler barrel : length 10-ft. ; diameter outside smallest ring 3-ft. lo-in. ; height of centre above rails 7-ft.; firebox casing: length 5-ft. 6-in., depth at front 5-ft. 1-in., and at back 4-ft. 7-in. ; heating surface : firebox 100 sq. ft., tubes 975 sq. ft., total 1,075 sq- ft. ; grate area 16.25 sq. ft. ; total weight in working order 31 tons. 18 cwt., distributed as follows: leading wheels 11 tons 14 cwt., driving wheels 14 tons, and trailing wheels 6 tons 4 cwt. 

The first series of these useful engines consisted of 46, which were built in the years from 1867 to 1874 inclusive, with the following works and running numbers :—