We illustrate to-day a new application of electricity to railroad
crossing signaling which the Pennsylvania Steel Company, of Steelton,
Pa., has just perfected. By its operation an isolated highway crossing
in the woods or any lonely place can be made perfectly safe, and that,
too, without the expense of gates and a man to work them or of a
flagman. It is surely a great improvement over the old methods, and it
is likely to have a large sale. In addition to considerations of safety,
possible saving in salaries to railroad companies by its use will be
great. This device is more reliable than a human being, and can make any
crossing safe to which it is applied. Its operation is described as
follows:
[Illustration: FIG. 2.--MAGNETO-ELECTRIC CROSSING SIGNAL]
The illustration shows the device as used on a single track railroad,
where it is so arranged as to be operated only by trains approaching the
crossing (i.e., in the form illustrated, from the right). A similar box
on the other side of the crossing is used for trains approaching in the
other direction. Two plates connected by a link, and pivoted, are placed
alongside of one rail, close enough to it to be depressed by the treads
of the wheels. By another link, one of the plates called the rock plate
(the one to the right) is connected to a rock shaft which extends
through a strong bearing into the heavy iron case or box shown, at a
suitable distance from the rail, within which an electric generator is
placed; the whole being mounted and secured upon the ends of two long
ties framed to receive it.
The action of this rock plate is peculiar. It is pivoted at the rear
end, not to a fixed point, but to a short crank arm, the bearing for
which is inclosed in the small box shown. As the first wheel of a train
which is approaching in the desired direction (from the right in the
engraving) touches it, it will be seen that it must not only depress it,
but produce a slight forward motion, causing a corresponding rotary
motion in the rock shaft which actuates the apparatus. On the other
hand, when a train is approaching from the other direction, or has
already passed the crossing, its wheels strike first the curved plate to
the left of the illustration, and by means of the peculiar link
connections shown, depress the rock plate so as to clear the wheels
before the wheels touch it, but the depression is directly vertical, so
that it does not give any horizontal motion to it, which would have the
effect of actuating the rock shaft. Consequently, trains pass over the
apparatus in one direction without having any effect upon it whatever,
the different point at which the same force is applied to the rock plate
giving the latter an entirely different motion.
[Illustration: FIG. 2.--MAGNETO-ELECTRIC CROSSING SIGNAL]
The slight rotary motion which is in this way communicated to the rock
shaft, when a train is approaching in the right direction, compresses a
spring inside the case. As each wheel passes off the rock plate, the
reaction of the spring throws it up again to its former position, giving
additional speed to the gearing within, which is set in motion at the
passage of the first wheel, and operates the electric "generator." The
spring is really the motive power of the alarm. A small but heavy
fly-wheel is connected with the apparatus, the top of which is just
visible in the engraving, which serves to store up power to run the
"generator," which is nothing more than a small dynamo, for the
necessary number of seconds after the rear of the train has passed. The
dynamo dispenses with all need for batteries, and reduces the work of
maintenance to occasionally refilling the oil-cups and noticing if any
part has been broken.
A suitable wire circuit is provided, commencing at the generator with
insulated and protected wire, and continued with ordinary telegraph
wire, which can be strung on telegraph poles or trees leading to the
electric gong, Fig. 2, which rings as long as the armature revolves. It
is a simple matter so to proportion the mechanism for the required
distance and speed that the revolutions of the armature and the ringing
of the gong shall continue until the train reaches the crossing; and as
each wheel acts upon the apparatus, the more wheels there are in the
train the longer the bell will ring, a very convenient property, since
the slowest trains have nearly always the most wheels. The practical
limits to the ringing of the gong are that it will stop sounding after
the head of the train has passed the crossing and before or very soon
after the rear has passed. A "wild" engine running very slowly might not
actuate the signal as long as was desirable, but even then it is not
unreasonably claimed the warning would probably last long enough for all
practical requirements, as a team approaching a crossing at eight miles
per hour takes 42 seconds to go 500 feet. All the bearings of any
importance are self-lubricated by oil cups, the whole apparatus being
designed to require inspection not more than once a month. The iron case
when shut is water-tight, and when duly locked cannot be maliciously
tampered with without breaking open the case; so that, the manufacturers
claim, it will not be essential to examine it more than once a month.
The parts outside the case are all strong and heavy, and not likely to
get out of order, while easily inspected.
The apparatus can be used for announcing trains as well as sounding
alarms, as the gongs can be placed upon any post or building. The gong
has a heavy striker, and makes a great deal of noise, so that no one
should fail to hear it.--_Railway Review_.
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