32 TECHNOLOGY. 
4. IncriveD Pranes. Where a considerable rise is to be overcome in ‘a 
railroad route, it is often preferable to concentrate the ascent at the termina- 
tion of the route, instead of equalizing it through the whole length of the 
road. Various methods have been adopted for overcoming these steep 
ascents, and we will describe some of the most usual of them. 
a. Self-acting Roads. Where loaded cars descend an inclined plane they 
are often made to bring up the empty cars ; such roads are called by the Eng- 
lish, self-acting roads. The motion is communicated by means of a rope or 
chain to which the cars are attached. This rope or chain runs in the middle of 
the road upon rollers (pl. 4, fig. 14, @), and upon the upper end it passes over 
a drum or wheel (jig. 13)*which lies beneath the surface at the top of the 
ascent. This wheel is from 6 to 16 feet in diameter, and revolves in a 
masonry chamber, over which are strong timbers which serve to carry the 
rails. Usually there are two roads side by side upon the ascent; when 
therefore the loaded cars are upon the left track at the top, the empty cars 
are upon the right track at the bottom, and as soon as the full cars are per- 
mitted to descend, they draw the empty ones up upon the other track. If 
the descent is so steep that danger is to be apprehended from the accelerated 
motion of the descending cars, a brake is applied to the large drum at the 
top, by means of which the motion is moderated and controlled. The 
rollers upon which the rope runs are formed in a variety of ways: pl. 3, 
jig. 19, is a plan of aroller used upon the Disseldorf and Elberfeld inclined 
plane; jig. 17 a side view of the roller and the box in which it runs; +g. 18 
is a longitudinal section upon a B of jig. 19; jig. 20, cross-section on ¢c D, 
jig. 19. The case, a, is secured to the timbers, e, e, and contains the bear- 
ings, c, of the roller 6, which is of cast-iron, the axle being of wrought-iron, 
and of a size according with that of the rope which it has to carry. The 
size and quality of the ropes upon an inclined plane are of the first impor- 
tance. Wire ropes are at the present time almost exclusively made use of, 
and as these may sometimes break, it is necessary to have the means at 
hand instantly to stop the descent of the cars ; this is accomplished by brakes. 
To the ascending cars, however, a self-acting arrangement is applied in the 
following manner: behind the last car hang one or more bars, 6 to 7 feet 
long, and 3 inches square, suspended to the car at one end, and shot with iron 
at the other. These bars trail after the car; and in case the latter attempts to 
descend, the point of the bar enters the ground and holds the car stationary. 
b. Inclined Planes with Stationary Engines. . It is almost exclusively in 
mines that a counter-weight can be depended upon to modify the motion 
of the descending cars; in other cases, where a loaded train of cars is to be 
raised or lowered, some other power must be resorted to, and this is usually 
steam. A short distance from the top of the plane is a drum, o (pil. 3, jig. 
16), lying horizontally with its axis perpendicular to the direction of the — 
rails; attached to this drum is a cog-wheel which engages with a pinion, 
upon the shaft of which is a fly-wheel and clutch; the shaft is driven by a 
steam-engine. The drum turns upon a cylindrical axis, from one end to the 
other of which it may be moved by a lever; it has also a brake attached to 
it, by which its motion may be controlled. 
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