March iS9o, the Pennsylvania Railroad ran a special, known as the "Aunt Jack " train, from Jersey City to Washington, D. C., 225 miles, in four hours and eighteen minutes. Change of engines was made at Gray's Ferry, Philadelphia, ‘vhich required a stop of four minutes, the actual run ning-time being four hours and fourteen minutes.
.Street- or out of consideration the unsnc cessfnl attempts, made even before the introduction of railroads (as already mentioned in the brief historical sketch), to construct a street-locomotive or steam-wagon, and the efforts in this direction by Dr. Robinson and by Watt (1759) and by Cugnot (1769), as well as the rather more successful construction by Evaus referred to under railroad-locomotives, the history of the subject to be discussed here begins only about 183o. It would seem as though the construction of a street-locomotive should have offered no difficulties ten years after George Stephenson had developed his railroad locomotive. But the uneven street, even the smoothest macadamized road, and still more the ordinary country road, differ so entirely from a solid and level railroad, with but slight grades and curves and constructed especially for locomotive service, that very peculiar and unexpected dif ficulties had to be overcome. But those who can comprehend the enor mous pressure exerted by the driving-wheels of a railroad-locomotive against the unyielding iron or steel rails to produce the adhesion on which depends the motion of the entire machine, will approach with hesitation the solution of the of moving a wagon or a traction machine by wheel-tires pressing against a comparatively soft and yielding street surface.
the smooth, even surface of ice success seems more possible, and the locomotive tried on the Neva and shown in Figure 3 (p1. lat) was not a total failure. It is constructed much like a railroad tender engine, with water-tanks saddled over the boiler, but instead of truck wheels is prOvided with sled-runners, and the driving-wheels have their peripheries set with sharp points. But the brittleness of ice remains an obstacle to'running often over any given track, which becomes more and more damaged by the points in the tires. Besides, the sphere of avail ability is limited. Since 1862, when this ice-locomotive was invented, nothing further has been heard of it.
before this (1846-1354), Boyden had endeavored to overcome the difficulty of the soft ground by a dragging track. As shown in Figure 6 (j51. m5), the track is pulled along by two driving-wheels moved by toothed gears. It consists of six flat pieces fitting into one another and loosely bolted to the driving-wheels. These pieces are successively laid by the engine itself in front of the driving
wheels. Although on a dirt road or in a field these flat pieces do not sink so deeply into the ground as would the driving-wheel alone, there is a greater tractive adhesion than the wheels would have on the ground. Guidance is effected by a truck with a steering-wheel, placed in front of the smoke-box. But, notwithstanding many favorable results, this loco motive is available for only a narrow sphere of usefulness, and, on account of its slowness, high price, and great cost of running, as well as the fre quent repairs required by the ingenious although complicated mechanism, it cannot compete under usual circumstances with the ordinary vehicle.
Traction 1862 there was tried another system, which depended simply on the friction of the tires on the street surface. The tires were rough or provided with projections and cross-grooves, or were entirely smooth, but almost as wide as the rollers used on macadamized roads. Figure 5 (/51. To5) shows another type. Close behind the boiler is the driving-axle, which is turned (as in locomobiles) by the single-cylinder engine on the top, a sprocket wheel and chain gearing being employed, while a steering-truck is arranged in front.
Schwar7kofif s Traction the Hamburg exhibition of 1862, the locomotive by Schwarzkopf of Berlin gained the victory over all other traction engines. This, with car attached, is shown in Figure 2. It differs from the preceding one in being provided with springs on the driving-axle as well as on the running-axle, and in having a twin link motion steam-engine. Both distributing motions—borrowed, of course, from the railroad-locomotive, but not sufficiently appreciated by former inventors of traction engines—have considerably contributed to the attain ment of a favorable result. The motion, however, is not effected directly, as with the railroad-locomotive, but through toothed-wheel gearing (seen to the left, under the boiler) placed between the engine and the driving axle, while steering is effected by a chain-pulley (visible to the right, under the front car) turning the running-axle, which is provided with small wheels. With a speed of one (German) mile per hour the running ex penses of Schwarzkopf's traction locomotive, with from five to six loaded cars attached, amount on an average to three pfennige per hundredweight per mile, inclusive of wear and tear and of interest on the cost of from 7000 to 8000 thalers ($5000 to $6000). This includes the wages of the crew and tollage. The weight of the locomotive is from 9000 to ro,000 kilogrammes (to to tons), and the maximum power from twenty to twenty-five horse-power.