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The Employment of Mechanical Motors on Tramways.

The introduction of a cheap and efficient means of communication is a question of much importance, and one of which the solution has occupied extensively the consideration of our leading experts. While the beneficial influence that railways have exercised on the districts with which they are connected, by leading to the expansion of commerce, manufactures, and agriculture, has largely contributed to the material progress of the country in general, outlying towns and neighbourhoods, too far distant from the main routes of thoroughfare to partake of any direct advantage from their development, are naturally anxious to reap an increased share of the benefits accruing from a closer connection with the exterior world. Many and various efforts have already been made to comply with these requirements, but the greater number of the projects have been failures, or where they have been carried out, the result from a financial point of view has been anything but satisfactory. These failures have for the most part arisen from the comparatively heavy cost of construction of even the lightest class of railways, combined with the expenses attendant on their working, and the parties interested have therefore given their attention to the question of producing a means of communication, which while capable of being more cheaply executed and worked, will not essentially alter the mode of transport.

The solution of a problem of such importance has, as may well be supposed, given rise to many different schemes; and the tendency of more recent investigations has been in the direction of substituting for horses an efficient mechanical motor as soon as such can be shown to be obtainable.

When this has been done, the question of "secondary railways" for the country may be looked upon as settled, because the construction of light tramways upon the principal country roads as they now exist really supplies an inexpensive railway, inasmuch as the entire cost of land, earthworks, culverts, and fences, and the greater part of the outlay usually required for bridges, ballast, stations, and gate-houses, will be avoided; and in regard to working expenses, the greater part of the official staff can very well be spared, while the important reduction in the proportion of dead to paying weight will materially reduce the cost of haulage.

The mechanical motor may either be in the form of a distinct engine coupled to a tram-car, thus resembling a locomotive and railway train, or it may be placed inside the car itself, and act directly upon the car wheels. Each of these modes of construction has its advocates, but it may be looked upon as established (as I propose hereafter to demonstrate) that the placing of the engine inside the car is to be preferred, as conducing to economy of working.

If we suppose the mechanical motor under both conditions to be in the form of a small locomotive, weighing two tons, and having a power equal to 15 horses, attached to an ordinary tram-car weighing about 2½ tons, and carrying 60 passengers, weighing say 4½ tons, or a load altogether of 7 tons, then such an engine would not, at any rate upon a perceptible gradient, be able to start its load, because the adhesion of the driving wheels, with only 10 cwt. upon each wheel, would not be sufficient to overcome the "vis page 4 inertiæ." The engine wheels in such a case would revolve upon the rails without producing forward motion. On the other hand, if the engine were placed inside the car, so that the car wheels themselves would be used as driving wheels, then the weight, or at all events a portion of the weight of the car and passengers, in addition to that of the engine itself, or in all 1 ½ tons per wheel, instead of half a ton, would rest upon these, and be available for the establishment of sufficient adhesion to enable the resistance to be overcome. It is quite true that there would be no great difficulty in loading the engine, say with 4 tons of lead, so as to obtain in that way a sufficient amount of wheel pressure to meet the requirements of the case, but there would then be an addition to the dead load of 4 tons, which would require so much additional haulage, and entail an increased expenditure for fuel and wear and tear of the roadway.

The ready stopping of the car is also effected more advantageously when the engine is placed within the car, than when it is separate, because when the brake action takes place in the lighter engine, the heavier car behind will strike it with a certain force, and the concussion will drive the engine forward for some distance before a complete stoppage is obtained, whereas, when the engine is in the car, the brakes act directly upon the car wheels with instantaneous effect.

These considerations will, I think, show satisfactorily that whatever may be the special form of mechanical motor selected, it should in all cases be placed in, and form an integral part of the car itself.

I now propose to describe the kind of car which I would use for the purpose, calling attention to the fact that thoroughly exhaustive trials, made in the presence of experienced judges, have confirmed the correctness of my views.

The principle on which the car is constructed is the same as that employed in America for ordinary railway carriages, the body resting upon two "bogies" or under carriages.

Between the bogie and the carriage body, springs and bearing plates are so placed as to secure the light and equable motion of the car. This kind of vehicle is common in America, and is remarkable for the ease with which, unaffected by its length of body, it moves round exceedingly sharp curves, the bogies turning freely under the car, and it is only the distance of the wheel centres in each individual bogie, and not the length of the carriage, which limits the radius of practicable curves. Such a long car, supported at each end on flexible springs, is easy for the passengers, and in consequence of the weight being distributed on eight wheels, instead of as is usually the case, on four, the wear and tear of the rails is proportionately slight, an advantage which is further increased by the diminished amount of friction due to the short distance of centres of the bogie wheels. With a view of affording a suitable place in which the engine may stand, the pin of one of the bogies is made hollow, and enlarged to several feet in diameter, and in this hollow pin is fixed the engine, which acts directly upon the bogie wheels underneath, and thus sets the whole carriage in motion. It is evident that the enlargement of the bogie pin will not affect the revolving movement of the carriage body upon it, nor will the engine in this position interfere with the arrangements for ascending and descending to or from the upper seats of the car at either end.

To allow the engine to be attached or detached with facility, the end of the ear is made to open on hinges, and a crutch is arranged under the body to be let down when required, so as to rest upon the solid ground, and by means of screws take the weight off the bogie, while the latter, with the page 5 engine resting upon it, is removed and replaced or exchanged for another when so required.

Springs are placed between the bogie plate and the carriage body, so as wholly to prevent any vibration caused by the engine from being communicated to the body of the car itself, the passengers thus being quite unconscious of the working of the machinery, the whole of which is separated from them by a double partition. While every annoyance of this description is thus provided against, the engineman can at all times have access to any portion of the engine and give it requisite attention.

It will be seen, that in accordance with this arrangement, the half of the weight of the carriage body and of the passenger load will rest upon the driving wheels, and by this means furnish sufficient adhesion to enable the engine to work with its full power, whatever that may be.

The force of adhesion being thus to a great extent independent of the weight of the engine, this weight can be reduced to a minimum, and the dead load decreased while the wear and tear of the roadway is diminished accordingly.

The car can of course move equally well with either end foremost, but as it is desirable that the engineman should, like the driver of a horse-car, be able to see the track before him, the end in which the engine is placed must always in practice be ahead. This necessarily involves frequent turning round of the car, to which there can be but little objection, as there are many different ways in which this turning can be conveniently effected, without the use of a turntable.

The most simple arrangement for the purpose, where there exists an open space at the terminus of the tramway, is to lay a circular road, and let the car run round it. When circumstances do not permit of this method being adopted, one bogie may be blocked fast upon the rails, and the other being turned across, can be made to revolve round the first as a centre. But, probably, the easiest of all will be to lay a triangular siding into a lateral road or street in the neighbourhood of the terminus. For instance, let A be the end of the track, and B the nearest side street before arriving at A. C and C′ are sidings laid in symmetrical curves from the main line to a point where they connect, d, and are prolonged for the length of a car to B. The car turns from the main line along C towards B, and is then backed on to it again over C′, when it arrives at A in a reverse position ready for its return journey. This operation will not occupy more than half a minute of time.

The bogie system is peculiarly adapted to the employment of a steering apparatus, and is therefore especially suited for use upon single lines of tramway, where it is constantly necessary to shunt into sidings. The same page 6 apparatus enables it also, in case of its getting off the track, to be easily brought again on the rails, as it is unlikely that both bogies should go off at the same time, and one bogie can be steered on again with so little trouble that the passengers would scarcely be aware of the mishap.

Many other cars of different patterns have been designed and built, but none of them comply with all the conditions specified above, and it is quite impossible that any four-wheeled car, with the unavoidably long distance between wheel-centres which this system entails, can have the same advantages as those afforded by the double bogies.

Although the foregoing paragraphs by no means state all the merits of the car which I have described, or enumerate all the inconveniences arising from the use of a separate engine, enough has I think been said to show, that of the two systems, the combined car and engine is decidedly to be preferred.

I would further remark, that a car on the double-bogie principle can be made of a size to hold 100 passengers as easily as it can be made to hold 20, and that it can be used on tramways or railways of any description.

Having now shown the manner in which a car with mechanical motor can be most advantageously constructed, it remains to be considered what is the best description of motor for the fulfilment of the objects in view. As is well known, engines have been made to be worked by means of gas, springs, compressed air, &c., but I think it will be admitted by the great majority of qualified judges that—

No power has yet been discovered which in point of cheapness, handiness, and security, can compete with steam.

The question to be determined is therefore this: Can steam be used in such a way as to fulfil all the necessary requirements? and I shall now endeavour to show that this question may be answered in the affirmative.

The difficulties which have to be dealt with in the outset are these:—

1st. The size and weight of the engine.

2nd. The noise caused by the working of the machinery.

3rd. The annoyance occasioned by the smoke from the furnace.

4th. The noise made by the escaping steam.

5th. The difficulty which the engineman necessarily experiences in keeping a good look-out ahead, and at the same time giving due attention to the regulation of the fire and other arrangements, which the control of the steam in the necessarily small boiler demands.

1st. The Size and Weight of Engine. Experience shows that an engine of from 15 to 25 horse power is required for the efficient working of an ordinary tramcar where there are any considerable gradients, and it is found that such an engine of 15 horse power can be made to weigh not more than 2½ tons, and to occupy a space of about 150 cubic feet, without steam of higher pressure than 150 lbs. being required. Such size and weight place on difficulties in the way of its being used in the manner above described.^*

2nd. Noise of Machinery. This can easily be got rid of by a proper mode of construction and careful workmanship in the details.

3rd. The inconveniences arising from tne smoke can be avoided by the use of one of the many recognized smoke consumers, or by burning only first-class coke in a form of boiler which secures perfect combustion.

4th. The noise of the escaping steam has hitherto caused serious objections to its use for tram-cars. In common locomotives the steam is made to escape through the chimney, because the draft so produced is necessary page 7 for the maintenance of an effective heat in the furnace, and this escape is attended by a mass of visible condensing steam, and a sharp puffing sound. If this means of supplying draft is dispensed with, a substitute must be found, and this substitute must be of such a nature as to be completely under the control of the engineman, so as to enable him to regulate with accuracy the state of the fire in the furnace, and consequently the supply of steam. But this is by no means easy, as the boiler in such an engine as is here referred to must of necessity be of very limited dimensions, with but little space for reserve steam, while it is not permissible to allow any escape through the safety valve. At the same time the demand made by the engine itself is exceedingly irregular, having to vary each time the working changes from a level road to a steep gradient, or from a full load to a light one, or during its frequent stoppages to take up passengers, stoppages which may be of longer or shorter duration according to circumstances. All these considerations render it necessary that the engineman should have the most complete control over the artificial draft by which the state of the fire and the supply of steam is to be regulated.

It must be assumed that the total absence of escape steam in any form is an unavoidable condition for a steam engine on a tram-car, as it will otherwise be looked upon as a highly objectionable nuisance by the inhabitants of the houses situated on the roads or streets through which it may have to pass, and will have to contend against great opposition from such persons, especially if they should happen to be owners of horses.

The principle which I have adopted is exceedingly simple, consisting of the use of a small noiseless fan which supplies the blast to the furnace, and at the same time effectually condenses the surplus and exhaust steam.

There is no difficulty in finding room in an ordinary tram-car for a condenser with from 1000 to 2000 square feet of condensing surface, though so much will scarcely be required.

An arrangement by which the cold air from the fan can be made at will to pass round under the scats on its way to the condenser, or to enter the latter direct from the fan, enables the apparatus to be used for warming the cars in winter.

In the cars of two stories which are now beginning to be very generally used, the warming of the upper story can easily be managed by connecting one or two pipes with some of the tubes of the condenser.

The air from the condenser, except in so far as it is used for warming the interior of the car, passes from the tubes directly into the ashpit of the engine, acting as a blast of hot air under the furnace, and the inconsiderable amount of power expended in driving the fan is more than compensated for by the more perfect consumption of the fuel.

The power of regulating exactly the amount of blast thus enables the engineman to ensure perfect combustion, or to reduce the heat at pleasure, and even, by stopping it entirely, to extinguish the lire if necessary. In this way the production of steam in the boiler can be controlled with the greatest nicety.

As the manner of producing draft above described can be used on almost any kind of engine, it is unnecessary to enter into further particular. concerning that which I propose to adopt; the supply of air to the furnace. and the condensation of the steam being provided for, the remainder becomes a simple mechanical problem, which has been already satisfactorily solved in practice.

5th. By this system of working the engineman is enabled to keep a sharp look-out upon the roadway ahead, at the same time that he gives the requisite attention to the action of his engine, all the cocks and levers to be page 8 used in stopping or starting the engine, regulating the blast, &c., being so placed as to be within his reach without his having to move. The furnace is made of such a size that it will not require to be replenished with fuel during a journey, and the condition of the fire can be effectively regulated, as above described, from one spot, while the water is pumped from the cistern into the boiler by a self-adjusting pump, and the cistern is supplied by the condensed water from the condenser.

It therefore appears that the engine above described entirely gets rid of the difficulties attending the regulation of the steam supply, and the suppression of visible or audible steam, while at the same time it possesses other important advantages. Thus it is only necessary to replenish the cistern with water once or twice in the course of the day, as the steam is constantly condensed and used again, and the water from condensation being perfectly pure, boiler incrustations, an important consideration in such small boilers, are greatly diminished. The blast of heated air to the furnace reduces the consumption of fuel, and the facilities for warming without extra cost the interior of the vehicles, will certainly contribute to the increase of their use in winter.

The engine will, as a rule, have power sufficient to draw more cars when required—an important qualification in the case of the contingencies of holiday or other abnormal traffic.

In working out the idea of "Rowan's steam-car," it is impossible to avoid being struck with the possibility of doing away with the heavy locomotives now so destructive to lightly-constructed lines. If it prove possible to get rid of the present weight of engines, it follows that iron roads may be laid down of a cheaper and lighter construction than has hitherto been considered necessary for railroads.

Again, if lines can be constructed cheaply and furnished with a cheap rolling stock, many places at present isolated could afford to connect themselves with existing trunk lines. If the Legislature will but sanction the construction of such lines on existing high roads, all the large expenses of railway making, such as earthworks, land purchase, fencing and bridges will fall away, and we shall soon see all country towns connected by an organised system of steam-omnibusses and goods-trucks.

There can be no doubt that steam-haulage on iron tracks is cheaper than horsing on an ordinary macadamized road. One steam goods-truck will transport 60 tons of goods 12 miles daily for twenty-five shillings. This includes driver, fuel, cleaning, oil, waste, and repairs and renewals.

With horses on the macadamized road, five tons at the most could be transported the same distance for the same money. It is the same with passenger traffic—one steam-omnibus would carry 300 passengers 12 miles for twenty-five shillings, while an ordinary omnibus might carry 30 the same distance for the same money; and the passengers in the horse-bus would not have half the comfort they would have in the steam-bus.

A steam-omnibus might thus earn daily by carrying passengers at 1d. per mile 3,600 pence (£15), all haulage expenses being £1 5s. This sum leaves a large margin with which to pay interest on capital and other working expenses.

In comparing such steam-trams with railroads, when it is an object to economise in construction, and to use rails only adapted for a very light traffic, it must be admitted that the rate of speed would be much slower, probably not more than half the speed of a railroad, but the public must be prepared to give up some personal comfort, if they can obtain page 9 regular and frequent communication at a low outlay in comparison with a railroad. The capital required would probably not be more than one-fifth, and the working expenses would be about one-half if as much.

The rolling stock and equipment of the line would cost about one-half, though it would give exactly the same accommodation to passengers. Another advantage on a steam-tram would be, that the train can be stopped in a few yards. This fact and the comparatively slow speed would render accidents impossible. Besides this passengers can be picked up at any point on the line, and the wear-and-tear of the road is reduced to a minimum.

There is no doubt, also, that such road-rails will be a great saving to parish authorities, as all the heavy traffic which now destroys their macadamized roads would be diverted on to the iron tracks, and thus the macadamized portion of the road would be spared. Mr. Ewing Matheson, M.I.C.E., in his book lately published, "Aid to Engineering Enterprise," has given great attention to the subject, and he says:—

"Although tramways for the conveyance of minerals and merchandise were in operation long antecedent to railroads, a new stimulus has been given to this branch of enterprise by the rapid extension of town lines for passengers. Bail tracks upon highways, for vehicles with flanged wheels will probably become more common; while, if steam-cars become fully established in towns, their adoption for longer distances on country roads will follow in many districts where the roadways are suitable. Traction by horse-power or by fixed engines, or by something other than locomotives, has been generally accepted as that which distinguishes tramways from railroads, but if the use of steam on highways becomes general, the classification, if it be retained, may also depend on the speed, and may so include in the category of tramways those lines on which the loads are carried by steam-cars. A rail track affords—after canals and navigable rivers—the cheapest means of transport, and the use of steam overcomes the greatest obstacle which has hitherto prevented an extended use of tramways. For while on level roads even horse-traction allows on a rail track an enormous saving in the cost of haulage over that incurred on an ordinary highway, occasional hills almost entirely neutralise the apparent benefits. But though a ruling gradient of even two percent, may thus effectually hinder the success of a horse-tramway, the latent or reserve force in a steam-engine overcomes the difficulty."

The grooved rails used on town tramways are generally unsuitable for service on country roads, and raised rails which cannot conveniently be crossed by ordinary vehicles are advisable; but as in many countries the the highways are or can at small cost be made wide enough to allow a rail track on one side without diminishing too much the space for ordinary vehicles, it might prove advantageous in a Colony needing development, and where new roads are being made to lay out such roads, so that a tramway for steam-cars might be added at a future time. If a line can be laid in this way many of the expenses incurred in a railway project for land and works can be avoided; and as the maximum speed need not exceed ten miles per hour, and as the cars can at such a speed be stopped within half their own length, no fencing of the track nor signal apparatus is necessary. A tramway of this sort might be of great convenience in wide, sparsely-peopled districts—as, instead of stations few and far between—passengers and light goods could be taken up on the route, or at any rate at all cross roads; platforms or cranes for heavier merchandise being only provided at special places. In districts with only a small traffic a more frequent, and therefore a more convenient service could be maintained than the same page 10 expenditure on a railway, even of narrow gauge, would allow. For instance, on a road ten or thirty miles long from a seaport or railway station, where a traffic of only one hundred passengers and 20 tons of goods each way per day had to be carried, one mixed train, for goods and passengers, would suffice, and if the load were divided over two or more trains, the mileage would be proportionately and unprofitably increased, as the train even for the diminished load must still have a certain number of vehicles. But if instead of one railway train, four steam-cars, two for passengers, and two for goods were running each way at suitable intervals daily, the service would be more convenient and probably cheaper.

With the view of assisting to carry out a system of tramways for steam-cars, we append four sketches as types of cars which may be found useful.

Fig. 1 is an open goods-truck capable of taking—say, 10 tons of goods. A few passengers may be accommodated in the compartment behind, or this may be altogether omitted. We should suggest keeping goods-trucks as much as possible of the same type as the waggons of the line to which the steam-tramway or light railway acts as feeder. This will avoid the expense and trouble of shifting cargoes at the junction.

Fig. 2 shows a composite car for two classes of passengers and luggage. The steam-car is shown dragging a goods-trucks after it.

If the gradients permit, there is no reason why any steam-car should not drag several waggons after it. The steam-car may be constructed to have the same power as a 15-ton locomotive.

Fig. 3 shows a steam-car built on the same plan as a railway carriage. This car could be attached to an ordinary train, if necessary, and proceed on a journey without shifting passengers—but this will not be advisable in passenger traffic. For light railways this car would be well suited.

The engine is 40 H.P., and when the car is loaded, there would be 14 tons on the driving wheels, while the total weight of the car with 60 passengers would not exceed 21 tons.

On a railway 60 passengers would require one 15-ton locomotive and two coaches, with a total train-weight of 36 tons.

In this car we have, therefore, the same tractive and adhesive force as in the railway locomotive, and the same accommodation for passengers as in the railway carriages, with a saving in haulage of 15 tons dead weight.

The total daily working expenses of such a car may be reckoned at about £2 10s.

Fig. 4 shows a car with several divisions for different classes of passengers. The height has been reduced as much as possible to meet the occurrence of bridges with low headway.

Fig. 5 shows a covered goods-truck, with the engine run out, while a jack supports the end of the car.

The question now is, what is to be the cost for mechanical power? There are many minds at work on this problem. It has already been settled by experience, that the ordinary running expenses for steam-power on tramways—and no other motor need meantime be taken into the comparison—can be for 3d. per mile run. The charge for maintenance and renewal of the steam-motor is yet to be settled by experience; but it may be estimated approximately as in proportion to the quantity of fuel consumed per mile run, relatively to locomotives on railways. It appears that in the year 1876, the average cost for repair and renewal of locomotives on railways in England was at the rate of 3¼d. per train-mile run; and, taking the maximum quantity of fuel consumed per mile run by a tram-locomotive, page 11 with a car, as 8 lbs. per mile run, against, say, 32 lbs. per mile run by railway trains—in the ratio of 1 to 4—it is safe to take, for estimation, the cost for repair and renewal of tramway locomotives at a fourth of 3¼d., or 81d. per mile. Allowing 1d. per mile, the total cost for steam motivepower on tramways may be taken at 4d. per mile run, as against 7½d., the cost for horse-power. The difference, 3¼d. per mile, amounts to 22 per cent, of the receipts, and to 7¼ per cent, per year on the capital cost. It thus appears that the saving by the substitution of steam-power for horsepower on tramways would afford a dividend of 7¼ per cent, on the actual capital expenditure. The prospect is even better than this, for the tramways to be constructed in the future will be made at a much more moderate outlay than the pioneer tramways, which, like many of the earlier railways, were constructed mainly for the promotion of private interests.