| Weight of engine, complete, 5 tons 4 cwt. | 11,648 | pounds. | |||
| Steam-cylinder—diameter | 7 | 3∕4 | inches. | ||
| Stroke of piston | 10 | inches. | |||
| Revolution of crank to one of driving-wheels | 17 | ||||
| Driving-wheels— | diameter | 60 | inches. | ||
| „ | breadth of tire | 10 | inches. | ||
| „ | weight, each | 450 | pounds. | ||
| Boiler— | length over all | 8 | feet. | ||
| „ | diameter of shell | 30 | feet. | ||
| „ | thickness of shell | 7∕16 | inch. | ||
| „ | fire-box sheets, outside, thickness | 1∕2 | inch. | ||
| Load on driving-wheels, 4 tons 10 cwt. | 10,080 | pounds. | |||
The boiler was of the ordinary locomotive type, and the engine was mounted upon it, as is usual with portable engines.
The steam-cylinder was steam-jacketed, in accordance with the most advanced practice here and abroad. The crank-shaft and other wrought-iron parts subjected to heavy strains were strong and plainly finished. The gearing was of malleableized cast-iron, and all bearings, from crank-shaft to driving-wheel, on each side, were carried by a single sheet of half-inch plate, which also formed the sides of the fire-box exterior.
The following is a summary of the conclusions deduced by the author from the trial, and published in the Journal of the Franklin Institute: A traction-engine may be so constructed as to be easily and rapidly manœuvred on the common road; and an engine weighing over 5 tons may be turned continuously without difficulty on a circle of 18 feet radius, or even on a road but little wider than the length of the engine. A locomotive of 5 tons 4 hundredweight has been constructed, capable of drawing on a good road 23,000 pounds up a grade of 533 feet to the mile, at the rate of four miles an hour; and one might be constructed to draw more than 63,000 pounds up a grade of 225 feet to the mile, at the rate of two miles an hour.
It was further shown that the coefficient of traction with heavily-laden wagons on a good macadamized road is not far from .04; the traction-power of this engine is equal to that of 20 horses; the weight, exclusive of the weight of the engine, that could be drawn on a level road, was 163,452 pounds; and the amount of fuel required is estimated at 500 pounds a day. The advantages claimed for the traction-engine over horse-power are: no necessity for a limitation of working-hours; a difference in first cost in favor of steam; and in heavy work on a common road the expense by steam is less than 25 per cent. of the average cost of horse-power, a traction-engine capable of doing the work of 25 horses being worked at as little expense as 6 or 8 horses. The cost of hauling heavy loads has been estimated at 7 cents per ton per mile.
Such engines are gradually becoming useful in steam-ploughing. Two systems are adopted. In the one the engine is stationary, and hauls a “gang” of ploughs by means of a windlass and wire rope; in the other the engine traverses a field, drawing behind it a plough or a gang of ploughs. The latter method has been proposed for breaking up prairie-land.
Thus, thirty years after the defeat of the intelligent, courageous, and persistent Hancock and his coworkers in the scheme of applying the steam-engine usefully on the common road, we find strong indications that, in a new form, the problem has been again attacked, and at least partially solved.
One of the most important of the prerequisites to ultimate success in the substitution of steam for animal power on the highway is that our roads shall be well made. As the greatest care and judgment are exercised, and an immense outlay of capital is considered justifiable, in securing easy grades and a smooth track on our railroad routes, we may readily believe that similar precaution and outlay will be found advisable in adapting the common road to the road-locomotive. It would seem to the engineer that the natural obstacles generally supposed to stand in the way have, after all, no real existence. The principal inconvenience that may be anticipated will probably arise from the carelessness or avarice of proprietors, which may sometimes cause them to appoint ignorant and inefficient engine-drivers, giving them charge of what are always excellent servants, but terrible masters. Nevertheless, as the transportation of passengers on railroads is found to be attended with less liability to loss of life or injury of person than their carriage by stage-coach, it will be found, very probably, that the general use of steam in transporting freight on common roads may be attended with less risk to life or property than to-day attends the use of horse-power.
The Steam Fire-Engine is still another form of portable engine. It is also one of the latest of all applications of steam-power. The steam fire-engine is peculiarly an American production. Although previously attempted, their permanently successful introduction has only occurred within the last fifteen years.