Charles Burrell and Sons: Road Locomotive
Note: This is a sub-section of Charles Burrell and Sons.
Extract from Steam Locomotion on Common Roads by William Fletcher. Published 1891.
Messrs. Chas. Burrell and Sons, of Thetford, Norfolk, were one of the earliest makers of road locomotives; they commenced the manufacture of traction engines fitted with Boydell's endless railway wheels in 1856, and from that early period down to the present time, they have occupied a leading position in this branch of engineering.
We have for many years closely watched the progress made by Messrs. Burrell in the design and construction of all types of road engines, and can fully endorse the statement made by The Engineer some time ago, who said: "Messrs. Burrell exhibited much fertility of invention in varying the design of their road locomotives for different classes of work." And as a proof of the soundness of their construction and workmanship, a few years ago the writer saw a traction engine of their make under repair after being in constant service for 22 years, and this engine was expected to do duty for some years to come after the repairs were completed.
Messrs. Burrell commenced the manufacture of Thompson's road steamers early in 1871, and previous to the date of the Royal Show they had delivered four of these engines to customers, three of the first being sent to Turkey, all of which were of the same size and design as the one exhibited and tested at Wolverhampton, shewn by Fig. 77, This road steamer had two cylinders, each 6 inches diameter, and 10 inches stroke. The boiler was of the "pot" description, the two driving wheels were 5 feet diameter outside the rubber tyres, which were surrounded by a chain of steel shoes, the single steering wheel was 3 feet diameter ; the steering wheel fork spindle passed upwards through a boss in a strong dome shaped casting, and was worked by a worm wheel keyed on it, driven by a worm on the horizontal steering handle. The cylinders were inverted, and gave motion to a two-throw wrought iron crank- shaft, containing between the throws the four eccentrics for the link motion, these eccentrics were forged solid with the crankshaft. "At each end of the shaft there was a sliding pinion to gear into a spur wheel, bolted on to the inner side of the driving wheels. These pinions, when in gear, gave the quick speed for travelling. The crankshaft, by means of a spur pinion and wheel, drove the second motion shaft which extended across the engine, and carried at its two ends two pinions, which could be slid into gear for the slow speed with the spur gear of the driving wheels. This arrangement of gearing is illustrated by Fig. 72, given under Messrs. Robey's name. The sliding pinions on the crank- shaft and the countershaft were controlled by levers, fixed on the ends of shafts which extended lengthways of the engine : those for the quick speed pinions were solid, and lay within the shafts for the slow speed. These latter shafts were hollow. The four handles were conveniently placed two on each side of the driver, and there was an ingenious arrangement of stops by which the driver was secured against inadvertently endeavouring to put the one speed into gear before the other was taken out. It will be seen that this disposition of handles sufficed for throwing out one wheel when turning sharp curves, as well as for putting in and out the quick and slow gear." The whole of the working parts were enclosed in a sheet iron case. The boiler was intended to work at 130 lb. steam pressure, and the Judges of the Royal Agricultural Society said that the steaming of the boiler during the trial was very irregular.
During the earlier part of 1871 Messrs. Burrell and Sons wisely discarded the use of the pot' boiler, which gave so much trouble, and adopted the locomotive form of boiler. The design of the engine was entirely rearranged to suit the altered type of boiler. Fig. 78 shows this engine, the first of which was made for the Turkish Government, and it was pronounced by The Engineer as one of the best designed road locomotives up to that time constructed."
Mr. John Head, in his paper read before the Institute of Civil Engineers, also said that this engine "was an excellent specimen of careful design and workmanship."
The horizontal engine was placed on the top of the locomotive boiler, the cylinders being fixed nearest the fire-box end of the boiler. The driving axle, coal bunker, feed water tank, and boiler were all mounted upon a wrought -iron frame, as shown and carried by the four rubber-tyred travelling wheels. The two driving wheels were 6 feet diameter, the axle being situated about midway of the boiler barrel ; the two leading wheels were 4 ft. diameter and placed close together. A single vertical pin rose from the front axle and was surrounded by a steel helical spring ; the steering was effected by a worm and worm-wheel in the usual manner. By the illustration, Fig. 78, it will be seen that the fire-box of the boiler travelled foremost, the fire-hole being at the side of the fire-box nearest the reader. An arrangement consisting of worm and wheel, pinion and rack, seen in the engraving, was fixed to the frame for raising or lowering the fire-box of the boiler when ascending or descending inclines. The two steam cylinders were each 7.25 in. diameter and 10 in. stroke. The engine had two speeds of steel gearing, the main spur gearing from the countershaft to the axle was provided each side of the engine. The gearing ratios were proportioned for running at four and eight miles an hour. It will be noticed that the greater part of the working details of the engine was neatly boxed in.
This engine was intended by Messrs. Burrell to have competed in the traction-engine trials of the Wolverhampton Show, but it was not finished in time, it was however exhibited at the show proper and attracted a great deal of attention.
An engine of the same improved design was made by Messrs. Burrell for working passenger service in Greece, in connection with a large well-constructed omnibus intended to carry 50 persons as shown by Fig. 79. This road locomotive, it will be seen, is similar in design to the one we have just described and illustrated, except that the chimney was fitted with an American spark catcher, and an awning was erected over the engine driver and steersman. The omnibus was mounted on four wheels, unlike the ones used by Messrs. Ransome for service in India, because it was thought that some objectionable features were avoided by using the old and approved type of 'bus' There was accommodation in the omnibus for passengers, and on the roof likewise, which was protected by a canopy. Another engine of similar design was sent to Russia. Fig. 80 shews this engine, from which it will be seen that the two cylinders were placed at the chimney end, each 6 in. diameter and 10 in. stroke. The driving wheels were 5 ft. diameter, fitted with rubber tyres and Burrells improved chain-armour or protecting shoes, shewn by Figs. 81 and 82 — the leading wheel was 3 ft. 6 in. diameter. The travelling speeds were two and five miles an hour. The working steam pressure was 130 lbs. per square inch.
Figs. 81 and 82 shew Messrs. Thompson and Burrell's improved shoes. It will be seen that the steel plates touched each other outside the tyre, and were tapered at the ends, each shoe being turned down so as to clip the angle iron ring on both sides, as shewn in the large scale section, Fig. 81. These shoes were a great improvement on Mr. Thompson's original ones, and answered well in practice.
In September, 1 871, some interesting trials were carried out by Messrs. Burrell and Sons, at Thetford, with two of the passenger road locomotives we have illustrated and described. The engines tried were the twelve horse power for Crete in Turkey, and the eight horse power for Russia, and the large omnibus already illustrated. The trials were witnessed by Colonel Risa Rey, and Colonel Mehemed Bey, of the Turkish Service, and others. The large road engine, weighing 10.5 tons, had the following load coupled up to it, two waggons loaded with pig iron, a portable engine, and a coprolite mill on wheels; the whole, weighing nearly 37 tons gross, the engine drew up and down the streets of the town at 5 miles an hour. In one place an incline of i in 18 was mounted without the slightest sign of any slipping; the engine would have drawn another 5 tons easily. The train was accompanied by an 8 horse power road locomotive for Russia. In the evening the 12 horse power traction engine was brought out again and attached to the omnibus. Men and boys swarmed over the *bus like bees, the engine drew the load up hill and down, in the neighbourhood of Thetford, at the rate of 9 miles an hour, and in some places attained the speed of 12 miles an hour The boiler was constructed for a working pressure of 150 lbs. per square inch.
The eight-horse power engine was then attached to the bus, and ran back to St. Nicholas Works faster than horses could go in regular service. After witnessing these trials the writer in The Engineer said: — "No difficulty whatever exists in applying steam on common roads to the purposes of passenger traffic."
Messrs. Burrell and Sons made a considerable number of these well-designed road locomotives for quick speed travelling in foreign countries, and a goodly number were made for farm purposes in Great Britain, in which case, the cylinders were placed near the chimney, like Fig. 80, and the crankshaft with the clutch forks and the fly wheel for driving fixed machinery were placed at the fire-box end within reach of the driver. We need hardly say that the reputation of the Thetford firm is more than maintained by the well proportioned, and very efficient traction engines turned out by them at the present time. Their two latest patented improvements consist, first, of a method of mounting spur-geared road locomotives on springs, and second, of an arrangement of cylinder on the compound principle whereby a single throw crankshaft may be used.
Fig. 83 shews their road locomotive fitted with the spring arrangement and all their latest ideas.
For a long time Messrs. Burrell have kept the important problem of mounting traction engines on springs constantly before them, and more than thirty years ago their chain traction engines were mounted upon spiral springs fitted into the axle boxes, many of these engines are still in use. It is well known that the mounting of chain road locomotives upon springs is a very simple matter, but the application of springs to a spur-geared traction engine is a more difficult one, hence some of the plans hitherto introduced have been much too complicated to be of real service. It is not only necessary to arrange the details so that the up and down motion of the main axle, when passing over rough roads, shall not affect the pitch circles of the spur-driving gear, or interfere with the proper action of the compensating apparatus ; but it is equally important that the springs should be free to act, without being influenced by the transmission of the power through the gearing.
The patent spring arrangement was introduced by Messrs. Burrell at the Newcastle-on-Tyne Show of the R.A.S.E., 1887, and has been fitted to 60 engines during the last three years, and given great satisfaction. The range of the springs is sufficient to allow the engine to be driven at high speeds over ordinary highways. We are informed that, as the speed of the engine is increased, the vibration appears to be reduced, and the engine runs as smoothly as a carriage. Fig. 84 is a transverse section. Fig. 85 is a part longitudinal section of the Patent-Geared Traction Engine, mounted upon springs, while Fig. S6 is an end view of the gimbal or universal joint. These illustrations are so clear that very little description is needed.
In Fig. 84, A is the crankshaft, from which motion is communicated to the countershaft B by means of pinions gearing into the spur-wheel C. The spur-wheel C revolves upon a fixed steel tube D, and is connected to the countershaft B by means of the universal joint E. The other end of the countershaft is carried in the bearing F, free to move up and down in the box G. The bearing F is connected by the link H to the axle box J (which is free to slide up and down in the guides S secured to the horn plates X) so that they both rise and fall together as the engine rides up and down upon the springs L. The pinion M and the spur-wheel N are prevented from altering the distance between their centres, and so getting out of gear by the link H, and have also sufficient clearance at the sides of the teeth to allow of any sideway motion caused by the action of the engine on the springs. The axle-box K is also free to slide up and down in the guides S, its motion in no way altering the distance between the centres of the gearing. As shown in Fig. 84 the steel tube D is carried quite across the engine and bolted to the box G, which is also of steel and fastened to the horn- plate X, thus forming a solid bearing for the spur-wheel C and a substantial stay to the horn-plates X, and effectually preventing them being twisted or buckled by the strains thrown upon them. The volute springs LL can readily be adjusted by tightening up the nuts under them, or can be quickly changed if necessary without taking any other parts of the engine to pieces. The front of the engine is carried upon one spring which is fitted in the fore-carriage casting, and can be easily adjusted by removing a cap in the smoke-box.
We will now describe Messrs. Burrells single crank system of compound cylinders. Fig. Sy shows the front part of a road locomotive fitted with the compound cylinders, which was introduced at the Windsor Show of the R.A.S.E., 1889.
The high pressure cylinder is placed diagonally over the low pressure cylinder, and the piston rods of both are connected to one long crosshead, which is equal in length to the distance between the two centres of the cylinders. This crosshead has inside flanges bearing against the edges of the motion bars, and thus presents a large surface for wear, and takes up any cross strain. The steam after leaving the smaller cylinder passes directly into the low pressure cylinder, all clearances being filled up as closely as possible.
The slide valves of both the high and low pressure cylinders are coupled together and driven by one link motion, so that beyond having two extra glands to pack, there are no more parts requiring attention than in the ordinary high pressure engine with one cylinder. Both pistons are always moving together at the same velocity, so that the flow of the steam through the cylinders is uniform, and immense power is developed in starting a load. Engines thus fitted are as easily handled as single cylinder engines. By this neat arrangement the full benefit of the compound system is secured, thus effecting a saving of 30 per cent, in fuel, and without any complication. Not only is there a saving in fuel, but the saving of wear and tear to the boiler also is most important, the work upon the boiler being lighter, and consequently the heat in the fire-box much less. This is owing to the low pressure at which the exhaust steam is discharged up the funnel. Compound engines work more noiselessly on this account, and are less liable to frighten horses upon the roads than single cylinder engines. The value of both these improvements is greatly enhanced owing to the fact that they can be applied to existing engines.
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