Steam Tender Trials
During his successful career at the head of the locomotive department of the G. N. R., Mr. Sturrock attempted to solve a problem that was at the time exercising many minds—the procuring of more adhesive and tractive force by the utilization of the dead weight of the tender.
While many inventors coupled the tender to the engine in such a manner as to distribute part of its weight upon the trailing wheels of the engine, Mr. Sturrock proceeded on much bolder lines, and patented an arrangement whereby the tender itself constituted a separate locomotive, deriving its steam from the same boiler as supplied the engine cylinders. In eftect, his ” steam tender” ran on six wheels connected by means of outside cranks and coupling rods, the axle of the middle pair of wheels being cranked instead of straight, and rotated by means of two 12-in. by 17-in. cylinders which were fitted under the framing, between the leading and middle pair of wheels. Fig. 29 shows the external appearance of one of these tenders.
Steam was received by means of suitable pipes direct from the engine boiler, and after serving its purpose was condensed, the operation being described in Mr.Zerah Colburn’s “Locomotive Engineering” in the following terms:—”The exhaust steam from the cylinders is delivered into a tubular condenser surrounded by the water in the tank, consisting of fifteen tubes 2-in. in outside diameter, about 12-ft. 8-in. in length, fixed into a reception box at each end. The first box receives the exhaust steam and delivers it through the tubes; the second is fitted with a waste pipe to carry off the uncondensed steam.
Apparently there were two distinct sizes of steam tenders built, one having 4-ft. 6-in. wheels, and weighing 29 tons 8 cwt. with the tanks full, and the others having 4-ft. wheels, and weighing 27 tons 15 cwt. in running condition. The wheel-base of both was the same, leading to driving wheel centres 8-ft.5-in., driving to trailing wheel centres 6-ft. 8-in., total 15-ft. 1-in.. with a total length over the buffer beams of 21 -ft. 7-in.
At the close of the year 1863 Mr. Sturrock made his first experiment in this direction by taking the tender of the old Sharp single No. 46, and converting it into a steam tender of the kind just described. In this form it was tried with a number of engines on the Great Northern Railway, and also appears to have been lent to the Manchester, Sheffield and Lincolnshire Railway Company, who subsequently, by the way, ordered six steam tenders from Messrs. Neilson & Co. in 1865.
The first G.N.R. locomotive definitely provided with a steam tender was No. 391, and almost immediately afterwards Nos. 393 and 394 were also so fitted, certain alterations being made in them to allow for the additional tax put upon the boiler by the introduction of two new cylinders. These changes comprised the enlargement of the firebox, the provision of a second regulator in the steam dome, and a re-arrangement of the feed pumps to permit of the pumping of hot water.
The engines were put to work on the London and Peterborough division, and at once showed themselves to be capable of hauling loads of from 40 to 45 loaded coal wagons over the ruling gradients of 1 in 200 on the main line, while on the level stretches of the Lincolnshire loop line they proved quite equal to 60 wagons, the ordinary loads hitherto worked on these two sections of the line being 30 and 35 wagons respectively.
400 Class Locomotives
Following the apparently successful result of these trials, it was resolved to extend the type, and a number of new goods engines being wanted at about this time to meet the growing requirements of the goods and mineral departments, the order was given that they were all to be built with steam tenders.
No fewer than 70 engines were comprised in this class, all of the standard six-coupled type, having driving wheels 5-ft. in diameter, cylinders 16-in. in diameter, with a stroke of 24-in., and in general dimensions were practically almost identical with the former engines of Mr. Sturrock’s design, as can be seen from the accompanying illustration, Fig. 30, except for the provision of a firebox considerably larger than those formerly fitted, which extended well behind the trailing axle, and consequently had its grate sloping somewhat steeply from back to front. The grate area was in some as much as 26 1/2 sq. ft.
These engines, which weighed 35 tons apiece, and the contract price for which with tender was £3,750 each, were delivered to the railway company in the order and by the makers named : Nos. 400 to 409 by Messrs. Kitson & Co., Nos. 410 to 419 by Messrs. R. & W. Hawthorn (makers’ Nos. 1248 to 1257), Nos. 420 to 429 by Messrs. Neilson & Co. (makers’ Nos. 1151 to 1160), Nos. 430 to 439 by Messrs. R. & W. Hawthorn (makers’ Nos. 1258 to 1267), all in the year 1865 : and Nos. 440 to 449 by Messrs. Neilson & Co. (makers’ Nos. 1171 to 1180), Nos. 450 to 455 by the Vulcan Foundry Co. (makers’ Nos. 554 to 559), Nos. 456 to 460 by the Avonside Engine Co. (makers’ Nos. 620 to 624), and Nos. 461 to 469 by Messrs. R. and W. Hawthorn (makers’ Nos. 1325 to 1333), all in 1866.
The leading dimensions of Nos. 450 to 455 were: cylinders 16-in. by 24-in. ; coupled wheels 5-ft. diameter, distributed equally over a 15-ft. 6-in. wheel-base; boiler barrel 8-ft. 10-in. long, 4-ft. 2-in. diameter, containing 180 tubes of 2-in. diameter; heating surface: firebox 112-96 sq. ft., tubes 969-3 sq. ft. ; total 1082.26 sq. ft. ; grate area 23.58 sq. ft.
Before the whole of these goods engines were delivered, however, it was discovered that, while the steam tenders might be considered a mechanical success, they were scarcely so satisfactory from an economic point of view. It was found that engines provided with them could haul trains which were largely in excess of the requirements of the time, and which, moreover, were of such a length as to be extremely unwieldy in handling; and this was, naturally enough, a serious difficulty on a line on which there exists a frequent necessity to shunt goods trains in order to clear the way for express traffic.
It was also found that the repairs bill for these engines and tenders reached an uncomfortably high figure, though there can be little doubt that this result was greatly contributed to by the carelessness of the men in charge, who viewed the question from their own standpoint, and could indeed hardly be expected to regard otherwise than with considerable disfavour an arrangement which gave them an additional “engine” to superintend. As a consequence of these disadvantageous experiences, it was decided to stop the output of steam tender engines, and orders were given to the makers that those engines still building were to be stripped of the steam gear of the tenders prior to delivery. At the time of this decision 50 of these steam tenders were said to be in use on the line, but within a few years the entire lot were improved out of existence by Mr. Sturrock’s successor, and the engines rebuilt with larger cylinders.”
More Notes
The whole class was designated J3 except for 439, which was J2 within its last 8 months. (Groves, vol 1, pg 112)
