AN IMPROVED MEANS OF CAUSING SIGNALS TO BE MADE ON RAILWAYS, AND OF OTHERWISE PREVENTING CERTAIN CLASSES OF ACCIDENTS ON SAME
Year: 1857

page_text: application for Letters Patent was not given within the time prescribed
by the Act.)
PROVISIONAL SPECIFICATION left by John Gray and John Wilson Gray
at the Office of the Commissioners of Patents, with their Petition, on
the 12th October 1857.
We, JOHN GRAY, Medical Doctor, and JOHN WILSON GRAY, both of
Rathgar, in the County of Dublin, do hereby declare the nature of the said
Invention of "AN IMPROVED MEANS OF CAUSING SIGNALS TO BE MADE ON RAILWAYS,
AND OF OTHERWISE PREVENTING CERTAIN CLASSES OF ACCIDENTS ON SAME," to be
as follows:-
Our Invention consists of an arrangement by which a succession of various
self-acting signals may be made on railway lines, which will indicate that a
certain time has or has not elapsed since a train has passed, and whether the
train which so passed has or has not reached a certain point in advance, and
thus act as checks and aids one to the other, the arrangement being such
that each train of carriages by the act of passing along the line of railway
may cause visible caution or time signals to be made, which will continue
visible for any regulated period which it may be deemed advisable to determine
on, and thus by their presence indicate to the parties in charge of any succeed-
ing train that a train has passed on in front within the regulated period; the
position of the signals enabling the parties approximately to estimate the
actual time that has elapsed since the train so passed; and may also cause
other, or danger, or position signals to be made which will continue visible
untill the train will have passed to a certain distance beyond the place where
they are so made, be the time occupied in said transit long or short; and may
cause the former to disappear when the regulated time may have elapsed, and

page_text: the other when the train has reached the specified distance in advance; and
may also cause other signals, either as time or as position signals, suited for
night use or for foggy weather, in the nature of explosive or fog signals, to be
laid at intervals on the rail in a position in which they must be exploded by
any succeeding train that may pass over the line within a given number of
minutes, or before the train which causes them to be laid has reached a
certain distance from the place where they are so laid, and will cause same to
be removed from said position after the lapse of such certain or variable
periods, as may be decided on; and may also cause a bar or other suitably
adapted contrivance to be raised to and in like manner to continue for a speci-
fied time (or untill the train which causes it to be raised shall have passed
forward to a certain distance as may be deemed suitable), in such a position
over or near to the path over which any succeeding train of carriages must
traverse, so as to come in contact with and act on a roller or other suitable
contrivance attached to a rod or bar which depends from the lever of a steam
cock or othe arrangement attached to the engine, so as to cause a steam
whistle to be sounded, or steam to be shut off from the cylinder, or otherwise
act so as by the force it may exert to cause the train to be stopped, or to
warn the driver that a train has passed within a certain time, or that the last
train that has passed over the part of the line then being traversed has not
yet proceeded beyond a certain distance.
In order to accomplish these ends, we place at intervals in the roadway,
between and parallel to the lines of rail, a lever, the fulcrum of which is so
place that one arm of the lever is much longer than the other. This lever
plays in a box or case sunk into the roadway, and is so fixed that the end
of the short arm is raised above the plane of the rails, the end of the
long arm being sunk considerably below that plane, the former pointing
in the direction in which the train is supposed to run, the latter pointing
in the opposite direction. Near to, and it may be nearly. on the plane of
the fulcrum of this longitudinal lever, we place a bent lever, having its
fulcrum at the junction of the short and long arms, and having a lateral
spur projecting from one side of the short arm, towards. the short arm of
the first described or longitudinal lever, so. that the depressing of the short
arm of the longitudinal lever will cause the spur to be depressed; and the
short, arm of the bent lever to follow the motion of the short arm of the
other lever, and the long arm to be carried upwards and elevated in the
roadway to such a height that it will nearly reach to the level of the axles of
the wheel of an ordinary railway carriage. This long arm so raised is suitably
shaped,, or may be furnished at its top with a broad roller, to break the shock

page_text: caused by contact with the dependent arm and roller from the engine, and
constitutes the elevated bar, herein-before described. To this long arm is
attached a rod or line, which is so connected with a horizontal bar pivoted at
one end on a platform placed on the roadway, or it may be outside the rail,
that this long arm on being carried forward and elevated, draws after it the
free end of the bar, which is armed with an explosive compound, and which
moves horizontally over its own platform, describing a portion of the arc of a
circle, the armed end, in part of its course, passing over and close to a portion
of one of the rails, so as to bring the explosive compound into a position to be
acted on the passage of the succeeding train.
In connexion with the first-described or horizontal lever we place another
lever, which extends across the line; it is fixed on a fulcrum, and has a
short arm, which passes under and is depressed by the short arm of the
longitudinal lever, and a long arm that is elevated at the same moment.
This long arm is connected by a line or rod with a red or other semaphore,
attached to a signal post in such a manner that when the long arm is
elevated by the passage of the carriages, as described, the semaphore rises
to the position of a right angle with the post, and this lever being retained
in the position to which it is thus brought by the same spring catch arrange-
ment, to be herein-after described, that retains the bent lever in the position,
it is brought to by the passage of the train, the semaphore will remain at right
angles to the signal post till the spring catch is liberated, as herein-after
described, when it will return to its normal position. On the last carriage of
the train we place a wheel or roller, or skid, so situated that its position when
the train is passing over the line will correspond with that of the first-mentioned
lever, placed longitudinally in the center of the roadway, and herein-befored
called the longitudinal lever. When this wheel or skid is fixed to the regu-
lated position for acting on the longitudinal lever, it comes in contact with the
short end thereof; when the train is passing over the line depresses it, and thus
depresses the short arm of the transverse lever, raises its long arm, and sets
the red semaphore or danger signal attached to the signal post, and at the
same time depresses the short. arm of the bent lever, draws forward the bar
armed with the exposive signal, so that the exposive compound will be over
the rail, and elevates the long arm of the bent lever to the position in which
it will strike against and act on the adjustment provided in the engine or other
part of the succeeding train for giving the special signal resolved on, as, a
whistle, turning off steam, or reversing steam, as before described, should a
train come up before the train causing these changes will have passed to a
certain distance. These several parts are kept in this their new possition by a

page_text: catch spring acting on one of the arms of the bent lever untill they are liberated
by the arrangements and action herein-after described.
A heavy weight, playing over a pully or a spring, is so arranged in con-
nexion with the bent lever that it will bring all the parts fixed above described
in connexion with that lever back to their normal position whenever they may
be liberated by the action of the train on its reaching the liberating apparatus
fixed a certain distance in advance. For such purpose the spring catch is
fixed on a lever or pivoted bar, and catches one of the arms of the bent lever
when that lever is acted on, as described, by the longitudinal lever and
retains it and the transverse lever in their altered positions. This spring catch
is connected forward to a liberating crank or lever, placed some hundreds of
yards in advance, by wires or rods suitably adjusted by means of pulley's, levers,
and cranks, and other requisite connexions, to give support and due direction
to the connecting rods and wires when acted on. When the train has reached
the place where the liberating lever or crank is situate, the special wheel,
herein-before named, acting on a lever suitably adjusted, or it may be one of
the wheels of the train acting on one of the rails, adjusted as a lever, acts
upon the liberating lever or crank, and by means of it on the connecting
wires and on the spring catch, so as to liberate the bent lever from the spring
catch, allow it and the horizontal bar armed with the explosive signal, and the
short arm of the transverse lever, and with it the red semaphore, to be all of
them returned to their respective places, and the signals thus removed."
The lever or crank for liberating the signals we place so far in advance that
the passing train reaches and fixes a second set of danger or position signals
before it reaches the liberating appratus, thus leaving one series of these
signals always set as it passes onward. The caution or time signal, which
indicates the time that has elapsed since the passage of a train, is a semaphore,
which we prefer to make green, attached to a post, which we also prefer to
have very different in appearance from the post of the danger or position
semaphore. We cause this semaphore to be acted on by a seperate transversely
laid lever, which may be acted on the first-mentioned lever, herein-before
called the longitudinal lever, or by a special one fixed in the same way at a
different part of the line, which in some cases we prefer, as these signals may
in certain cases, with advantage be placed further apart than the danger or
position signals. The lever for this signal is also placed at right angles with
the rails, and when pressed at its shorter end is elevated at the other. This
longer end we connect by a line to the index arm of the semaphore, and it
acts as a weight to draw down the semaphore. When this end of the lever
is raised it liberates the semaphore, which is pivoted on the signal post, and

page_text: so balanced that on being liberated the signal or index arm instantly starts out
at right angles to the signal post, where it remains, after giving the caution
signal, untill it is gradually brought down again to its former position by the
descent of the longer end of the lever, which is retarded in its descent by its
attachments to a piston that plays in a cylinder. This cylinder, which with its
adjustments is in the nature of a pump, and which we prefer to furnish with
the expansive ring piston head, known in Dublin as the Invention of Mr. John
Wakefield, of the Inchicore Works, is rapidly filled through a large valve by
the sudden ascent of this long arm, which draws up the piston, thereby opens
the large valve, and fills the cylinder with a liquid, it may be air, or mercury,
or spirit, or other liquid which is not congealable by ordinarily low tempe-
ratures. The cylinder is slowly emptied by the descent of the piston, which,
being pressed on by the heavy end of the lever as it is descending, closes the
large valve, and expels the said liquid slowly and at à reguated rate through
a small nozzle, valve, or aperture, formed of incorrodible material. If air be
not the liquid used, a hermetically sealed reservoir is attached. The descent
may also be regulated by having the long arm of the lever attached to the
moving wheelworks of the common clock arrangement, which are so well
known as not to require special description. The long arm of the lever is
connected to one end of a cord or line, which is rolled round the barrel of the
wheel, which in a clock receives the cord of the moving weight. To the other
end of this line is attached a light weight, which serves to wind up the lever end
of the cord on the barrel, by its unwinding its own end whenever the lever end
is left free by the elevation of the lever, as described. When the carriages
have passed away, the lever acts as a moving weight to this wheel, and the
usual clockwork with escapement and pallet regulates the descent with
sufficient precision for all practical purposes, the pendulum being dispensed
with, and a "crutch" only being used, the weight will set the train wheels in
motion.
The arrangement of the mechanism attached to the engine may be varied
according to the class of signal resolved on. If it be a whistle, or a suitably-
adjusted rod, fixed as a lever close to the lever or key of a steam cock, and
projecting downwards, may be made to open the cock by being pressed back-
wards by the elevated arm of the bent lever herein-before described, a catch
5 being so arranged as to hold the upper arm that acts on the steam cock in the
position to which it would be brought by the return of the elevated arm of the
bent lever, and thus cause the whistle to continue to sound till the driver
would release it. An analogous arrangement would cause the action of the
elevated bar to act on the valve that shuts off steam, or on the levers for

page_text: reversing the action of the engine. This class of arrangement is, however, so
well understood as not to require further explanation.
In certain cases, and for some of these signals, the special longitudinal lever,
above described, and the special wheel or skid, herein-after described, may be
dispenced with, and a portion of the rail adjusted for the purpose of acting as
a lever; or a special portion put in may be so arranged that the passage of
the wheels of the train of carriages over it may act on it as on a lever, and
depress the secondary levers in the same manner as does the longitudinal lever,
above described. When we apply the caution or time semaphore signal and
the danger or position semaphore signal at the same place, one post may be
made to serve for both, the caution being attached, say, above, and the danger
below, or vice versa; and we cause the transverse lever for the time signal to
be so far removed from the lever for the position signal, that the spring catch
will not influence the former. In connexion with the time semaphore a second
or red semaphore might be used, that would disppear in a shorter time than
the green or caution semaphore, the same regulating mechanism acting on
both, as also on a fog signal, to be removed earlier than the caution signal.
Any or all of the signals herein-before described may be made as time
signals, without the catch and its liberating mechanism, which makes the
duration of the signals depend on the position to which the train has reached,
and not on the time that has elapsed; and the bar that carries the explosive,
or night or fog signal, may be made with phlanges, or hollow, so as to contain
a supply of explosive signals, to be advanced in succession to the requisite
place by a spring, as often as required; the end of it and the position of it
with respect to the rail it traverses being so arranged that neither the bar
nor the rail will be injured by the passage of the train over the explosive
compound.