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In support of the view that steam may be applied to this kind of traffic, we have, in the last number of the London Mec. Mag.; an illustrated account of the fifty-third traction engine built by Aveling & Porter, of Rochester. In this engine there are some good points. The steam-jacketed cylinder is in accordance with the practice of Watt, which has of late been revived, and recommended, especially by D. K. Clark, the best authority on locomotive practice. The steering gear is simple and effective; I believe Gurney was the inventor of it; it is shown in some engravings of his carriages. But it is not applicable for high speed and flexible springs. The whole arrangement, being without springs, is simple and cheap, but of course it is too slow for city traffic; and, from observation of a well built traction engine, I am of opinion that on soft roads a low rate of speed will be found disadvantageous, because there will not be sufficient momentum to pass over soft places.
I differ from Mr. Aveling, and from all the English traction engine projectors, in regard to gearing. This engine is geared to make twenty turns to one turn of the wheels. Let us consider this. I have calculated that the Great Britain locomotive, with eight-feet wheels, consumes five per cent. of its power in sliding its valves. D. K. Clark estimates that six per cent. is consumed in some locomotives, whose wheels, I presume, are smaller; and his authority corroborates my estimate. Now, if we keep the same boiler and the same speed on the rails, but use four-feet wheels, we double the friction of the valves, and so on, until, when the wheel is reduced to 4.6 inches diameter, the engine will barely slide its valves. Now, if, instead of gearing, this traction engine had reduced its wheels, they must have been 3.9 inches to get the same number of turns. per mile that the engines now make. But the speed is one-twentieth of that of the Great Britain; hence the parts are smaller, and the valve smaller, and the friction proportionably less, but still it is 6.15 per cent, of the gross power. If four-feet wheels, with direct action, were used, the valve friction would be .005-one-half of one per cent, a saving of .0565—or nearly 55 per cent. of the gross power;, and the loss of steam in the ways and clearances is much greater than it would be in a large cylinder working slowly; and the friction of piston, crosshead and gearing consumes a large per centage of the power. Mr. John A. Reed, of this city, built an engine, some years ago, in which some complex gearing was used; and when he removed it, the engine could draw more, although the engines made fewer turns per mile.
I hold that it is best to use wheels of moderate size, with direct connection--that is, a turn of the wheels to each turn of the engines. There is but one objection to this--the loss of heat from the cylinders. But I design to jacket the cylinders, and to lag the jackets, and in some cases to put the cylinders close to or within the smoke-box; in this way I believe I can avoid much loss of power from condensation,
In another point I differ from them. Instead of spikes, spuds and other contrivances to get adhesion, I put as much as I can of the drawn load upon the drivers, making their rims broad enough to bear whatever weight is necessary for adhesion with smooth tires.
Here is a drawing representing a two-wheeled pleasure carriage, connected to a steam wagon, the connection being made to a bar or transverse spring under the driving axle, and the total weight of the drawn carriage being about one-half on the driving wheels, but not resting on the springs of the steam carriage, and therefore not affecting the relative level of the engines and driving axle.
The act of parliament wisely prohibits projections on tires that work on public roads; and it is not at all necessary to use them, except there is greasy mud or ice or snow. On clean roads the adhesion is greater than on railways, so much that the wheels of my steam carriage, which would slip with 130 pounds on iron rails, do not slip with less than 180 pounds on pavements, and have gone up a hill over fresh broken stone with 190 pounds pressure, and without slipping.
Boydell's engine has what is called an endless railway, and its friends claim that this ségures it against slipping. I don't see how this can be; the wheels run on iron rails, without other hold than common locomotives have, unless the cycloids take the strain, and are made liable to be broken by it. If this be the practice, I think the repairs will cost too much.
For city traffic, except what ought to be carried at a speed equal to that of passengers, so as not to hinder passenger carriages, I am confident that gearing is not desirable. But if you wish to move boilers, columns, buildings, and other bodies of over twenty tons, then it may be used; and an advantage may be gained which has not yet been credited to steamyou'may move at a speed much slower than that at which horses work to the best advantage; you may move at half a mile per hour, or less, and thus avoid injury to pavements by jolting, and likewise avoid injury to your wheels; and at the same time you may work with a small boiler. Such slow vehicles should not be allowed in the principal thoroughfares except at night.
The cost of haulage by traction engines is given in Young's work entitled “Steam on Common Roads." The reports in this book show that the cost is from a third to half the cost by horse power, at two and one-half to three miles per hour, -that is, at the speed most advantageous for horses. As the speed is made greater or less than this, the economy of steam power, compared with horses; becomes greater.
Second, as to noise. Horses' feet make more noise than the wheels of light carriages, but less noise than the wheels of carts and omnibuses, and about as much noise as the wheels of rail cars, t, The steam blast in locomotives makes less than the noise of a tenth part of the horses that would be required for equal work. But the steam blast may be silenced, or dispensed with, and a fan substituted. The dummies of the Hudson River railway condense their steam, and use fans. Grice & Long's steam cars use large cylinders, and make two turns to one turn of a thirtyinch wheel, so as to expand the steam to a low pressure, and subdivide it into very small puffs, and thus reduce the noise to an insensible amount. I adopt the device of Gurney, which is, te exhaust into a chamber of ten or twelve times the capacity of the cylinder, from which the exhaust flows in a steady current like air from a smith's bellows, and inakes no noise except on steep inclines. It is generally believed that this arrangement involves more back pressure than the usual puffing blást; but Mr. A. F.
Smith, who tried it on the Lehigh Valley railway, considers that its loss by back pressure is not sensibly greater than the loss by the usual blastpipe.
There is a relation between gearing and the steam blast. Mr. Wm. S.. Hudson, superintendent of the Rogers’ Locomotive Works, approves of gearing for the traction engines, to such extent as to make a quick succession of small puffs, rather that a slow succession of large puffs, because the quick puffs keep a constant and nearly equable current of air through the fire, and the strong puffs, at long intervals, alternately disturb the fire, and throw out. coals, and then leave the draft weak until the next strong discharge of steam.
Now, by the plan of Gurney, the exhaust chamber may be made to equalize the draft, if it be proportioned to the time between the puffs. If the engine has large wheels, and move slowly, the exhaust chamber must be large; if it move at moderate speed, a small chamber will suffice; if it make four or five turns per second, no chamber is needed. Therefore, the complexity of gearing is not necessary to equalize the draft; it is not so effective an equalizer as the exhaust chamber or the fan, nor is it 80 silent.
Lifting sparks is an evil to be carefully avoided in street engines. It is a nuisance that ought to prohibit any engine which is not nearly free from it. It is to be avoided, partly, by avoiding such fuel as wood, charcoal and gas coke, and by using solid anthracite, and hard coke that is made expressly for locomotives. When I burn charcoal in my steam carriage at night, it throws out sparks to such an extent as to light the road sufficiently; and when a steam fire engine which burns wood, has worked an hour, you may see the pavement strewn with charcoal all around it.
It is also partly avoided by a large grate and a deep fire box. The dummies on the Hudson River railway have fire boxes forty inches deep. I design them from thirty to thirty-six inches deep for the small boilers of steam carriages; and my observations have been sufficient to satisfy me that large grates, deep fire boxes, heavy and tough fuel, and a steady draft, will make a cleanly engine; and that the dirt from thirty steam cars will be less than the dust worp from the pavement by one horse.
Third: as to smoke, or carbonic acid and nitrogen. The seven horses of an omnibus, in the twenty-four hours, mix into the street air more carbonic acid than a steam omnibus would mix into it, and the nitrogen is in proportion, because the car would project its gases upward with such velocity that they would soon be carried over the city, whereas the horses blow their breath downward, and mix it with the air we have to breathe. The gas nuisance is, therefore, much the greatest with horse power. As to smoke, it is a disgrace to the railroad companies that they have allowed it in cities. They had only to use coke, while in the streets, in order to avoid smoke; and, had they done so, there would have been no objection to their using locomotives in the streets of New York, as they were allowed to do in Brooklyn until their indecency disgusted the people, and the people drove them off. On rails, and still more on iron floors, the friction could be lessened, so that the power, and therefore the gases, would be reduced to a third of what they must be on stone pavements.
I contemplate certain small improvements which will lessen the consumption of fuel in the streets. I design to heat the water at the stations up to the temperature of the steam, and fill the boiler at the stations, and not feed it on the way. This will save a quarter of the fire on the road, and a quarter of the boiler surface, and the use of pumps, and will make the engines, on the whole, lighter. A Giffard injector will be carried, but never used except in an emergency. By using all such means that are conveniently practicable we may reduce the noxious gases to much less than they are with horse power-less than half on stone pavements, and less than a sixth when horses are superseded, and we have iron floors.
The dummies condense their steam. I have in this Club suggested that in the winter we may, in a future and more civilized age, remove the snow from the streets as soon as it has fallen, and preserve it to condense steam in summer. Mr. Wm. A. Lighthall, who is known as the designer of the engines of several first class steam vessels, has an air-surface condenser which he believes will be efficient on steam carriages. And we have engineers, both here and in England and France, who believe that compressed air may be used instead of steam, when machine vehicles have come so much into use that compressing stations can be supported. But, in the beginning, we must be content to keep the steam invisible, and shoot it upward so that it may be blown away from the city. This is done in locomotives that keep their steam dry. Steam-jacketed cylinders help to do it; superheating steam helps to do it; and the heat wasted in upright tubular boilers helps to do it; that is, the exhausted steam, mixing with hot gases in the chimney, becomes so hot as to dissolve in the air without becoming cloudy. If you watch the cloudy steam from an engine that does not exhaust into a chimney, you will see that it soon dissolves into the air, and ceases to be visible; but locomotives that keep their steam dry, send it out so hot that it dissolves in the air before it has time to become vesicular, or cloudy.
Fourth, as to danger. Were I to build a steam carriage that would be frightened by a wheelbarrow, or a push-cart, or an elephant, or locomotive, or by any strange object, the ultra conservatives would regard it as a serious objection to my carriage, and would not allow it to run, at the risk of killing people. But when an inexpert driver fails to control a timid or even a frisky horse, that is nothing new, and therefore they don't object to it. I claim that the steam carriage is, in this respect, safer than the horse; it cannot be frightened, and has no will of its own. If your horse frightened my carriage I would agree that it should be forever prohibited; why, then, should you not allow that if your horse has been trained in cruelty, and is afraid of every strange object, he should not be suffered to go in crowded streets where he may at any moment kill infirm people? I should be glad to ask Mr. Rarey if he could not easily train horses so that they would consider locomotives rather agreeable companions. I think he could. I know it has been done; 'and I think he could teach others to do it; and the small minority of horses that would be frightened by steam carriages could easily be got to like them. It is an exaggerated apprehension of the disputatious opponents of every new idea, that they do not themselves originate, and not the timidity of well used and well trained horses, that has excited so much objection to steam carriages and rail cars, on the assumed but not proven ground that they are less safe than horses. If steam cars should displace all the horses now working the passenger traffic, all the accidents from the fright of cart horses, fancy horses, and all other horses remaining in use, would be less than the accidents now occurring from the fright of the horses that would be displaced by the steam cars.
The other danger apprehended is the explosion of boilers. Col. Maceroni, who built a steam carriage that ran very efficiently, in reply to an inquiry as to the safety of his boiler, placed himself and his two children on the carriage, fastened down the safety valve, drove the fire, and actually bursted the boiler, and that without disturbing anything but the ruptured part. Jacob Perkins frequently had his cast iron tubes burst under 750 pounds pressure, but never had a brick thrown from the furnace, and it is a well established fact that high pressure steam does not scald. I have had water from a high pressure boiler blown into my face without scalding. The principle of subdivision of a boiler into small compartments may be carried so far as to secure absolute safety.
Some locomotive boilers on the New York and Erie railroad have barrels forty-eight inches in diameter, made of quarter inch plates, single riveted, and have been run whole trips with 200 pounds pressure. I design boilers for steam carriages twenty-four inches in diameter, of quarter inch plates, double riveted. The double riveted joint was found by Fairbairn's trials to be stronger than the single riveted, in the proportion of 70 to 56, or 10 to 8; bence, my boilers are two and a half times as strong as these locomotive boilers, and will bear 500 pounds as safely as they will bear 200. But I don't propose to work them above 150 pounds. With this excess of strength they are no more liable to burst than a building is to fall.
I have tried the subdivided tubular boilers, but have not succeeded in making them produce steam well, and I find that I can vaporize more water with a common boiler of 160 feet of surface, than Ogle & Sumner's did with 250 feet in a boiler of the subdivided kind. It is, therefore, expedient for me to use abundance of metal in the shell, rather than attempt to improve the boilers that are naturally safer, while I have not adequate capital. When I have sufficient capital I intend to experiment upon them, and to neglect no reasonable means of safety. Two engineers of acknowledged talent have patented steam generators that are unquestionably safe, and will, I believe, make steam fast. They have promised the exclusive right of them for common road and street locomotion to a company, if I can form one with adequate capital.
Fifth, the cost. The average cost per mile, of locomotives on the Illinois Central railroad, for seven years, was sixteen and two-third cents; on the New York Central it is from twenty to twenty-one cents, wood being the fuel; on the Baltimore and Ohio fifteen cents, with coal. The small tank engines built by Danforth, Cooke & Co., work for six cents per mile. The cost per ear per mile, for haulage, is less than two cents, at a speed of over twenty miles per hour. The contract price of drawing cars by horses at less than six miles per hour, on the Hudson River railway, has been twenty-five