IMPROVEMENTS IN SIGNALLING ON RAILWAYS, AND IN APPARATUS OF MEANS EMPLOYED THEREFOR
Year: 1872

page_text: PROVISIONAL SPECIFICATION left by James Pinkerton at the Office
of the Commissioners of Patents, with his Petition, on the 12th
November 1872.
I, JAMES PINKERTON, of Blackfaulds, in the County of Lanark,
North Britain, do hereby declare the nature of the said Invention
of "IMPROVEMENTS IN SIGNALLING ON RAILWAYS, AND IN APPARATUS OF MEANS
EMPLOYED THEREFOR," to be as follows, that is to say :—
This Invention, which relates to an improved system of signalling on
railways, has for its object to prevent collisions thereon, and it consists
in providing an arrangement of mechanism whereby, when an engine or
train has passed a given signal and the person in charge of the signal
apparatus fails or neglects to raise the arm of the said signal to such
position as to warn the driver of a succeeding train approaching the
signal on the same line of rails, the engine or train, first referred to, in
passing over the rails at a given point situate between the signal post and
the signalman's box, raises the arm of the signal into the proper position
to warn the driver of a succeeding engine or train, and at the same time
brings into operation an arrangement of mechanism which rings a bell

page_text: on the said succeeding engine; or the mechanism may be employed
to open a whistle or to shut off steam from the said engine.
The apparatus employed to effect the former of these objects consists
of a shaft extending across the line of railway at a lower level than
that occupied by the peripheries of the flanches on engine or carriage
wheels; the shaft is caused to project beyond the outer rail and a pulley
is placed on the said projecting portion around which is passed the wire
or chain communicating between the signal and the lever which
operates the same; an inclined plane is also fixed on the shaft at the
inner side of the outer rail, and which is so adjusted on the shaft as to
be in position to be acted upon by the flanch on one of the foremost
wheels of the engine or first vehicle in a passing train at such time as
the arm of the signal is down or signals the line clear for a succeeding
engine or train. Thus when an engine or train has passed the signal
post, and if the signalman fails to raise the signal arm so as to warn the
driver of a succeeding engine or train, the flanch on one of the foremost
wheels of the engine or train first referred to in passing over the inclined
plane moves the shaft on which it is fixed through the arc of a
circle, and thereby pulls the wire communicating between the signal-
man's lever and the signal arm, by which means the said arm is raised,
and thus protects the engine or train first referred to from being run into
by a succeeding engine or train, and at the same time the signalman's
lever is moved into the position which it occupies when the signal arm is
raised by the signalman. In order that this may be effected the clutch
with which the said lever is usually provided to retain it in position is or
may be dispensed with, and the lever itself may be formed curved
and provided with a counterweight to retain it in the position to which
it has been adjusted.
The second object embraced by this Invention, namely, to warn the
driver of an engine or train that the signal to which he is approaching
is in its raised position, is effected by attaching to the weighted end of
the lever which counterbalances the weight of the signal arm one end
of a wire or chain, the other extremity of which is attached to a frame
mounted on small rollers or wheels, and placed at any desired distance
from the signal post on the side thereof opposite to that at which the
apparatus herein-before described is situate. On the upper side of the
frame an elliptical or other convex surface is formed or fixed, and which
is arranged parallel with the rails; the frame is placed on an inclined

page_text: plane situate at right angles to the rails, and its position is so adjusted
that it is furthest away from the rails when the signal arm declares the
line clear; but when the signal arm-is raised, the depression of the
weighted end of the counterbalancing lever allows the frame to run
down the inclined plane, so that the convex surface thereon is in close
proximity to and projects above the rails. Thus when an engine or train
passes over the line at this point a lever depending from the engine is
raised by the said convex surface, and may either strike a bell on the
engine or open the whistle, or the said raising of the lever may
be employed to shut off steam from the engine, and thereby bring it to
a stand.