Modern English Traction Engines
At the present moment the question of rapid transport over common roads is occupying the attention of many minds. It is a fascinating subject, and one that has been dealt with very fully of late. England is sadly handicapped in the race, owing to an oppressive law that will not allow motor carriages to travel more than four miles an hour in the open country and two miles an hour when passing through towns. Since this law was passed, some good steam carriages have appeared in Great Britain, but they have moved about only at slow rates on the public roads, and shown their powers at fast speeds on private grounds alone.
Practically the light steam carriage enterprise was strangled in its cradle. In the meantime, however, a considerable amount of thought has been brought to bear upon the heavy slow moving traction engine. The modern traction engine cannot be dispensed with, in spite of the irritating opposition that is raised against it by a class of persons who object to the employment of any power, except animal power, on the highway.
For many years the traction engine industry in England remained principally in the hands of three or four leading makers, but at the present time there are about twenty firms engaged in the enterprise, all of which are in a position to supply the engines. There are more minds devoted to the improvement of the traction engine than ever, and there are more men interested in its development, so that it is no matter for surprise that the efficiency of the engine has recently advanced in leaps and bounds.
It is not many years since the English traction engine showed very little evidence of drawing office care in its design. The details looked as though they had been thrown into position, giving the engine a very hap-hazard appearance. There was little attempt to cover the gearing or working parts, and the movement of these grotesque and miscellaneous wheels, rods, and exposed crankshaft, caused the engine, when in motion on the road, to look like a factory out for an airing. We do not wonder that horses and some men were terrified when they met these wheezing, groaning, and smoking abominations on the highway.
But all this has been changed: the engines have undergone a series of revisions ; every part has passed through the mill of the mind. Pleasing and graceful appearance is now considered to possess much value, and many have aimed at this with happy results.
To design a really efficient and neat looking traction engine requires a considerable amount of experience, and an ability of a special kind. Even many years of experience alone do not furnish the requisite qualification. The designer of a good traction engine must be able to see, at a glance, whether a detail is of the necessary form and strength for its intended purpose. Mathematical knowledge does not render much help. In the case of some designers of good traction engines, this kind of knowledge was limited; but this deficiency has never disqualified a practical man from producing an engine that was soon a general favourite among buyers. Calculations as to proportions appear to be quite useless; the sizes and strength of gearing, brackets and shafts have been, and can be, decided only by years of actual work, failure after failure leading eventually to success.
We know of one engine over the drawings of which figures ran wild; calculations were made by the square yard, but the machine, when built and put to the test, proved a disastrous failure. Another agricultural locomotive comes to mind, which was designed several years ago by an engineer with no experience in traction engine manufacture. While the drawings were in preparation no suggestions were forthcoming from the foremen, or officials, as all the staff was new to the branch. The first engine was quickly built, and, without any delay, was taken from the shops and put through some severe trials on the road. It was taken ten miles away from the works the first day, and made to mount a very steep hill in fast gear. During these trials no alterations or failures of any kind took place, neither ere any modifications made in the engine after the test, but it was speedily dispatched to the purchaser, who had work of various kinds waiting to which the engine was at once applied. This number one traction engine gave every satisfaction and was christened “Success”. Many more engines were afterwards made to the same plans, and the makers occupy a prominent position among the firms who produce good traction engines.
The engine is shown in Fig. 1, not because it is a modern type, but because some interest is attached to it.
The following types of traction engines are made in England at the present time :—
1. Agricultural locomotives for threshing purposes.
2. General purpose traction engines, used for threshing and for hauling occasionally.
3. Road locomotives for continuous hauling work on roads.
4. Light traction engines for running at quick speeds for parcel and passenger service in foreign countries.
5. Self-propelling ploughing engines.
Any of these engines can be made suitable for burning wood, straw, reeds, cotton-stalks, or oil as fuel. They may be mounted on springs or fitted with spring wheels. They are made on the simple or on the side-by-side compound plan.
There are two systems of construction which must be referred to here, in order to save much repetition in the description of the engines. They are termed four-shaft, or inside gear traction engines; and three-shaft, or outside gear engines. In a four-shaft engine, there is a crankshaft, two countershafts, and a main axle; in a three-shaft engine there is a crankshaft, one countershaft, and a main axle.
Messrs. Aveling & Porter, of Rochester, England, have for many years taken a leading position in the manufacture of traction engines. Fig. 2 shows one of their compound road locomotives, specially intended for continuous hauling work on the roads. The high and low pressure cylinders are placed side by side at the smoke-box end of the boiler, the pistons and connecting rods actuating a double-throw crankshaft.
In order to place the slide valves close to the top of the cylinder, the valve rods are arranged on an incline. Some of the gearing is placed inside the box brackets between the bearings. The side plates of the boiler are carried upward, and at the top a strong casting is secured. In this casting are combined the bearings for the crankshaft and the two countershafts, forming a substantial arrangement for keeping the spur gearing in proper working condition.
A worm barrel is provided for the steering chains to coil on, preventing the chains from mounting, and for taking up the slack. The feed pump is fixed on the boiler barrel, the suction pipe leading direct into the pipe which connects the two tanks as shown. The engine parts are boxed in, and the gearing is covered. The equipment is complete, and care has been expended on the design and construction of this engine so as to render it in every way worthy of the name it bears. Such engines leave little to be desired on the scores of simplicity, strength, durability and economy in working.
The compound engine shown in Fig. 3 is built by Charles Burrell & Sons, of Thetford. A dynamo is mounted on the smoke-box end of the boiler, for illumination at night. The engine is mounted on springs which secure a great saving in wear and tear of the working parts. An awning covers the tender and some of the working parts of the engine, and a rail is fixed round the coal bunker in order to increase the fuel capacity. The water lifter and hose are attached to the fore tank as shown. It is very evident that a good appearance has been aimed at with the best results. This firm has probably built a larger number of types of road engines than any other maker, and not one of these types has fallen short of success.
Fig. 4 shows a twin compound agricultural locomotive made by Messrs. Foden Sons & Co., of Sandbach. The cylinders are steam jacketed and well lagged. The front cylinder covers have each a cylindrical guide cast with them as shown. The guides are bored and turned at one setting, which makes them absolutely central with the bore of the cylinders. On the top of the guides is fixed a Porter governor which actuates a throttle valve in a direct manner. The sides of the box brackets are made of boiler plates, riveted to the arch plate, and stiffened by transverse plates.
All Messrs. Foden's engines are mounted on springs. The axle and the countershaft are securely held together by links on each side, and the bearings for both these shafts slide in a strong bracket. On the top of each bracket there is a circular box containing a large square steel spiral spring. The weight of the hind part of the engine and the boiler, passes through the springs to the main axle. There is also a similar spring on the fore axle, kept in place by a cylindrical turn plate.
The tires of the driving and leading wheels are made of tough cast-iron, the former being shod with steel diagonal strips. The driving wheels are nearly seven feet in diameter; the advantages of large drivers are too well known to need any remark here. It will be noticed that a larger number of spokes are adopted than usual, the iron being of a smaller section. The water in the supplementary tank under the boiler barrel, is heated by a portion of the exhaust steam. The pump draws its supply from this tank.
Another road locomotive, specially built for hauling showmen's paraphernalia from town to town is shown in Fig. 5, and is manufactured by Messrs. John Fowler & Co., of Leeds. The engine illustrated, enables circus proprietors to be independent of the railway companies, the cost of road haulage being from 50 to 80 per cent, less than by rail. The owner of this engine says :—
" I may tell you that in passing through Jarrow-on-Tyne, the engine and its train of ten wagons had to travel in awkward streets, parts of the train being in three streets at one time, forming something like an S. In the winter time I frequently travel thirty miles a day with a load of nearly fifty tons."
The engine is of the double-crank compound type, and is well-mounted on springs. The vertical play due to the action of the springs has been registered automatically when passing over rough roads. When running at two miles an hour the vertical movement is half an inch; when running at four miles an hour it is about an inch; and when going at the rate of six miles an hour, the vertical play is one and a quarter inches. A dynamo is fixed on a platform at the front, driven by a belt from the flywheel of the engine. Messrs. Fowler have supplied a considerable number of these engines, for drawing from thirty to fifty tons.
Fig. 6 represents one of Messrs. Fowler's single-cylinder, general-purpose traction engines. The illustration is self-explanatory. All the best features of a modern traction engine intended for threshing and general work are embodied in this example. The high speed governor and equilibrium throttle valve render the engine particularly suitable for steady driving.
A newly designed traction engine made by Messrs. Richard Garrett & Sons, of Leiston, is shown in Fig. 7. It is intended for threshing and general work. The single cylinder is bolted to the boiler barrel in the usual manner, having a wide flange all around for taking a good bearing on the boiler. The ordinary slide bars are dispensed with, and a bored guide takes their place. The usual link motion has been discarded to give place to a single eccentric reversing gear of simple construction, patented by Messrs. Mann & Charlesworth, of Leeds.
Messrs. Garrett's engine is of the four-shaft type. The governors are of the Pickering type. The engine is a substantial piece of work and possesses all the up-to-date accessories of the modern traction engine, such as a winding drum and wire rope, a brake, and a water lifter and hose pipe for filling the tank from a brook on the road side. The drawbar on the tender has straps on the sides for taking the strain, thus preventing the pull of the engine from making the tank leak.
Fig. 8 represents a very neatly designed agricultural locomotive, made by Messrs. R. Hornsby & Sons, of Grantham. There are several features of interest that distinguish this engine from those already described. It is an outside gear engine. The box bracket plates are riveted to the firebox shell, having transverse plates riveted in between them to give them the requisite stiffness. A neat bracket carries the two slide bars, the governor and throttle valve spindle, the valve rod guide, and the bar for the reversing gearing. The whole of the steel driving gear is cased in to preserve it from the dust, and to suppress noise.
The dome on the top of the cylinder is in direct communication with the steam jacket round the barrel of the cylinder, and these spaces combined form a large reservoir, from the highest part of which the steam enters the stop valve. The governor is of the cross-armed or approximate parabolic type, very sensitive in work. A wooden platform is provided on the side of the boiler barrel, from which the engine driver can reach to oil or clean all parts of the engine. Underneath this footboard a very large toolbox is hung. A round tray is fitted on the front axle for carrying loose tools, chains, etc. All the handles and levers are conveniently arranged, so that one man can, if required, drive and steer the engine.
The agricultural locomotive shown in Fig. 9 and built by Messrs. Mann & Charlesworth, of Leeds, possesses several novel features. The ordinary link motion reversing gear has been dispensed with, and in its place the firm's patent single eccentric reversing gear has been applied. This enables one eccentric and rod to do all that is required in working expansively when running forward or backward, and for reversing the motion. The eccentric is shifted from full forward to full backward without altering the lead. Its movement resembles that of the parallel ruler, as in any position it remains parallel to the centre line of the engine and at right angles to the crankshaft, and the driving pinions for the two speeds are placed between two of these bearings, but outside the box bracket. The governor is fixed over an equilibrium throttle valve in the cylinder. By using steel castings in place of cast-iron, the weight has been considerably diminished without reducing the strength, or limiting the efficiency.
In Figs. 10 and 11 are shown both sides of a very well designed agricultural locomotive, made by the well known firm Messrs. Marshall, Sons & Co., of Gainsborough. These traction engines have been improved from time to time and possess all the latest devices suggested by a long experience. It is impossible to speak too highly of the efficiency and good workmanship of Messrs. Marshall's productions. The cylinder is thoroughly steam-jacketed, and the steam supply, the circulation and the drainage of the jacket have received careful attention. Bored guides are used instead of the usual slide bars, and the outer end is supported by a bracket that serves as a guide for the valve rod, and a stand for the governor and throttle valve spindle, as well as for the details of the reversing gear.
The sides of the tender are flanged so as to reduce the riveting, increase the strength and give the tender a neater appearance. Some of the gearing is placed in the box bracket; the remaining gearing outside the plate is effectively covered in to protect it from dust and dirt. The steerage worm wheel is placed inside the bearing, instead of outside, as is the usual practice. The engine is fitted with strong compensating gear, a slip winding drum and all the usual tools and appliances for rendering the engine complete and ready for any emergency to be met with in regular threshing or occasional hauling work.
Another prominent firm engaged in the manufacture of traction engines, is Messrs. J. & H. McLaren, of Leeds. In Fig. 12 is shown one of their newly designed agricultural locomotives. This engine is of the four-shaft type. The weight of the engine has been considerably reduced, in fact there is a desire among the best makers to take away all superfluous material in the details and to replace heavy cast-iron brackets with much lighter ones made of steel. By these alterations the strength and the efficiency of the engines are considerably increased. Messrs. McLaren, too, have adopted the bored guide. The engine is a thoroughly sound and trustworthy piece of workmanship, the design embodying the improvements suggested by seventeen years' experience.
Fig. 13 shows a single cylinder, general-purpose traction engine made by Messrs. Ransomes, Sims & Jefferies, of Ipswich. This engine is suitably equipped for use in the colonies. The greatest care has been bestowed on it, so as to render it as simple as possible. The number of details has been
cut down to the utmost limit, but in no case has real efficiency been sacrificed thereby. All the latest improvements have been embodied in the design, while the workmanship is of the highest description—equal to the work produced in the best railway locomotive shops. The boiler is made entirely of steel and suitably stayed for a working pressure of 140 pounds per square inch. Before being erected the boiler is subjected to a water test pressure of 240 pounds per square inch. The plates are flanged by hydraulic pressure, and the riveting is also done by the same means.
The steel shafts and main driving axle are carried in brackets, fitted into the side plates of the firebox shell, which are extended upward and backward for the purpose. These side plates are stiffened by flanged transverse plates, which are riveted in as shown. This forms a box in which the crank, the eccentrics and the first motion gearing are nicely arranged. The engine is fitted with compensating gear on the main axle, so that it can turn sharp curves without loss of tractive power. This gear relieves the axles of much strain, and, when necessary, the differential gearing can be locked, so that both wheels revolve with the axle. On the main axle the winding drum is also fixed. This drum is so made that the steel rope can be paid out as the engine travels forward,—an arrangement that effects a great saving of time.
Suppose we wish to haul a heavy load up a steep hill with the drum and wire rope. Instead of taking the engine up the hill and pulling the rope out by hand, as was formerly done, it is only necessary to attach the rope to the wagon to be hauled up and run the engine to the summit of the hill, paying out the rope all the time. By pressing down a spring pin the drum is then put into gear, and the rope is wound up without a moment's loss of time. The whole of the spur gearing is made of cast-steel, so that breakages are rarely heard of, and the wear is reduced to a minimum. Two speeds are provided, — one for drawing heavy loads up hill, or over bad roads, at two miles an hour; and the other, for lighter loads on level and good roads, giving a speed of four miles an hour. The arrangement of this gearing is such that only one lever is required for changing the speed, and one pinion is thrown out before the other is put in gear.
All the shafts, axles, piston and valve rods are of steel. The pins, joints and general wearing parts are made of ample dimensions for reducing the wear to the utmost, while special care is devoted to the proper case-hardening of these parts. The cylinder is steam-jacketed, so that neither air nor water can be trapped and retained in the jacket. When running on the road, the governor is not used, but when the engine is used, as it can be, for driving machinery by a belt from the fly wheel, the governor is required.
A second tank is fitted under the boiler barrel, carrying an extra quantity of water, and both tanks are connected by means of" a pipe. A good bit of road can thus be covered by less frequent stoppages for water. A cab is provided for sheltering the driver from the sun or the rain; it also covers the box bracket and the working parts in it. A foot plate and ladder are fitted for the use of the driver when oiling or cleaning the engine. On the front axle there is an iron box for carrying the anchors, the hauling chains, frost spikes, cotters, etc. The engine is complete in all particulars, thoroughly economical in fuel, efficient in work, handy to manage on the road and has no details likely to get out of order or give trouble. The whole work is very sound and good, and fairly represents an example of one of England's best make of traction engines.
Fig. 15 shows one of Messrs. Ransomes, Sims & Jefferies' improved agricultural locomotives of the single-cylinder type. A large number of these engines have been manufactured and are doing excellent service on farms.
A few years ago there was every in dictation that the compound traction engine would become very popular, but this result has hardly been realized. The compound engine has been adopted in many cases, but those makers who have specially boomed their compound engines still continue to make a good number of single-cylinder engines. Some firms say, "We can supply traction engines made on the compound principle, but we recommend the single cylinder engines, as, with the latest improvements, they work very economically and have only half the number of parts." There are other manufacturers who are prepared to supply compound engines, but who are rarely asked for them. The greater proportion of their orders are for single-cylinder engines.
For continuous hauling work, however, the compound engine must be recommended. If this type of engine is worked at the full boiler pressure of 150 lbs. per square inch, a saving of thirty per cent, in fuel and water will be secured. The noise produced by the exhaust steam also is reduced, which is an advantage. The shocks upon the crank-pins, gearing and other working parts are less severe. An auxiliary valve is provided which allows high pressure steam to enter both steam chests, and both the cylinders exhaust into a common exit pipe (the compound principle being suspended for the moment), enabling the engine to start readily with a heavy load behind. As soon as the engine is under way the valve is closed. A relief valve is fixed on the low-pressure steam chest.
For threshing purposes the compound engine cannot be so fully recommended on account of the reduced steam pressure employed for threshing,—from 80 to 100 lbs. pressure being quite sufficient. Not only so, but for this work the attendants are often very unskillful, so that it is an advantage to have the simplest possible engine. The first cost is also a consideration with the threshing fraternity. While on the subject of cylinders we may refer to the proposal to bolt the cylinder on a wrought steel fixing or girder, instead of bolting the casting direct to the boiler barrel as heretofore. The base of the cylinder and the seating are planed, so that, having a flat surface, the joint is more easily made and retained. None of the bolts pass into the steam space. For export engines this method of construction possesses important advantages. Beyond this there does not seem to be any great value in the plan.
Now that steam pressures are steadily creeping up, some makers have experienced trouble in keeping the joint tight under the cylinder, around the steam inlet, but if the joint is properly fitted there will be no fear of leakage. In Fig. 16 is given a section of a traction engine cylinder in order to show the steam opening from the boiler, and one method of making a steam tight joint. It will be seen that the cylinder is tapped to receive a pipe which passes through the boiler plate; on the under side of the plate a properly shaped washer is fitted, and a nut is screwed tightly up to it On the bottom end of the pipe a steam collector is also screwed.
In Messr’s Ransomes’ traction engines this steam joint trouble is nicely remedied. The cylinders in their engines have no steam inlet hole under the foot, but the steam is conducted into the cylinder by a separate elbow so arranged that the joint is easily made and rarely leaks after it is once fixed in position. The bolts around the cylinder foot have to make their own joint only, and if the bolts are turned taper under the head and fit the holes in the boiler plate, iron to iron, without red lead, they will never leak.
The cylinders are always steam jacketed. The outside shell is generally made of good iron, and the liner is made of specially hard iron and is forced into its place by hydraulic pressure, the annular space between the liner and the shell forming a roomy jacket, as shown in Fig. 17. This jacket space communicates direct with a chamber on the top of the cylinder, which answers the same purpose as a dome. By the arrangement shown, circulation of the jacket steam is secured.
The steam chests of compound engines are often placed on the outside, so as to be easy of access for examination. When placed between the cylinders, they are troublesome to get at, unless they are arranged some distance above the centre line of the cylinders, in fact, as near to the top of the cylinder as possible, the valve rods and valve faces being inclined so as to point to the centre of the crankshaft. The enormous friction of a large slide valve for a single-cylinder traction engine has been obviated by the application of the compound engine; the high pressure slide valve is of small dimensions, and, working on the compound principle, it is partially balanced.
For want of space we have been compelled to omit some remarks with illustrations of rigid wheels, compensating gear, winding drums and driving gearing. We illustrate, however, at least one form of spring wheel. Inventors from the earliest times have been busy devising spring wheels for traction engines. Some of these answered well, and many were made, of a few different types, but most of them soon showed some constructional defect,—generally in the quality of the steel of which the springs were made. The constant jar on the road caused the material to become so brittle that the spring spokes, or the volute springs between the arms and the tires of the wheels, sooner or later gave way, and there are very few spring wheels at work at the present time.
One of the latest examples of a spring wheel is shown in Fig. 14. The engraving represents Mr. Link's wheel,
in which the weight carried is equally distributed through the various details of the wheel. One extremity of the twelve spiral springs is attached to the double spokes, and the other end is secured to the tee-iron rings. By withdrawing the pins, any of the springs can be removed or replaced without interfering with any other part of the wheel. On the spokes, near the sole of the wheel, are cast-iron blocks, which do not touch the inside of the tire, but sufficient space is allowed for their movement, and in order to prevent any play sideways, steel plates are fitted on to the blocks which tit in and fill up the space between the webs of the tee-iron rings.
When a new agricultural locomotive is sent to a customer, it is usually put to a few days' heavy threshing work on several kinds of grain. If the samples are satisfactory, the engine is next made to haul the threshing machine through a ploughed field. If the land be wet, so much the better test of the hauling power. The engine is next coupled to a heavy load on the road, and, if possible, on a steep gradient. In days gone by we have seen engines deeply engulfed in a ploughed field and unable to extricate themselves; but the modern traction engines of the best makers are rarely if ever found wanting in any of the trials. They will traverse nearly any kind of land with a threshing machine and stacker behind, and on good roads they will haul nearly as much load as is given in the above table of dimensions. This table is extracted from the writer's book, "Steam Locomotion on Common Roads," in the hope that the dimensions will enhance the value of the paper.
It may be thought that the engines illustrated present a somewhat similar appearance. This is true respecting the general arrangement of the parts, but as regards the details it is very wide of the mark. There are some features of the modern traction engine, which have certainly settled into a beaten track, but we see no reason for regret if the path leads to highest results. Slight alterations and improvements are constantly taking place. Keen competition among the manufacturers compels them to make frequent modifications of the design, so as to keep abreast of the times. Finality will probably never be reached, but the traction engines described here possess all the well-tried devices, show the best in design and construction and are undoubtedly the survival of the fittest.
Table of Dimensions of Simple and Compound Road Locomotives
|             ||             ||             ||              |
|Nominal horse-power||              6||              8||              10|
|Indicated horse-power||              30||              40||              50|
|Diameter of cylinder, single||              8 in.||              9 in.||              10 in.|
|Stroke of cylinder, single||              12 in.||              12 in.||              12 in.|
|Diameter of high-pressure cylinder, compound||              5¾ in.||              6½ in.||              7 in.|
|Diameter of low-pressure cylinder, compound||              9 in.||              10 in.||              11 in.|
|Stroke of both cylinders, compound||              12 in.||              12 in.||              12 in.|
|Working steam pressure, single||              125 lb||              125 lb||              125 lb|
|Working steam pressure, compound||              145 lb||              145 lb||              145 lb|
|Revolutions of engine governing, per minute||              180 rpm||              180 rpm||              180 rpm|
|Revolutions of engine on the road, per minute||              240 rpm||              240 rpm||              240 rpm|
|Total heating surface, single||              120 sq. ft.||              160 sq. ft||              200 sq. ft.|
|Grate area, single||              4½ sq. ft.||              6 sq. ft.||              7½ sq. ft.|
|Total heating surface, compound||              108 sq. ft.||              144 sq. ft.||              180 sq. ft.|
|Grate area, compound||              4¼ sq. ft.||              5½ sq. ft.||              7 sq. ft.|
|Diameter of driving wheels||              6 ft.||              6½ ft.||              7 ft.|
|Width of driving wheels||              14 in.||              16 in.||              18 in.|
|Slow gear ratio||              25 to 1||              27 to 1||              30 to 1|
|Fast gear ratio||              17 to 1||              18 to 1||              20 to 1|
|Diameter of leading wheels||              4 ft.||              4½ ft.||              4¾ ft.|
|Width of leading wheels||              8 in.||              9 in.||              10 in.|
|Diameter of main axle||              4½ in.||              5 in.||              5½ in.|
|Diameter of crankshaft||              3¼ in.||              3½ in.||              3¾ in.|
|Diameter of crankpin||              3½ in.||              3¾ in.||              4 in.|
|Pitch of first motion spur gearing||              1¾ in.||              2 in.||              2¼ in.|
|Pitch of second motion spur gearing||              2 in.||              2¼ in.||              2½ in.|
|Pitch of third motion spur gearing||              2¼ in.||              2½ in.||              2¾ in.|
|Diameter of compensating gear bevel wheels||              2¼ ft.||              2½ ft.||              2¾ ft.|
|Pitch of compensating gear bevel wheels||              2¼ in.||              2½ in.||              2¾ in.|
|Slow traveling speed in miles per hour||              4 to 5||              4 to 5||              4 to 5|
|Fast traveling speed in miles per hour||              2||              2||              2|
|Diameter of fly wheel||              4 ft.||              4½ ft.||              5 ft.|
|Width of fly wheel||              6 in.||              6 in.||              6¼ in.|
|Weight of engine in working trim||              10 tons||              12 tons||              15 tons|
|Approximate load hauled on fairly level roads||              18 tons||              25 tons||              32 tons|
|Total width of engine||              6 ft.||              6¼ ft.||              6¾ ft.|
|Total length of engine||              16 ft.||              18 ft.||              18½ ft.|
- Cassier's Magazine, Jun 1896 pgs. 135-150