IMPROVEMENTS IN RAILWAY SIGNALLING APPARATUS
Year: 1881

page_text: LETTERS PATENT to Thomas Murray Ford, of Great St. Helen's, in the
City of London, Shipowner, for an Invention of "IMPROVEMENTS IN
RAILWAY SIGNALLING APPARATUS.".
PROVISIONAL SPECIFICATION left by the said Thomas Murray Ford at
the Office of the Commissioners of Patents on the 2nd June 1881.
THOMAS MURRAY FORD, of Great St. Helen's, in the City of London, Shipowner.
"IMPROVEMENTS IN RAILWAY SIGNALLING APPARATUS."
My Invention relates to railway signalling apparatus, and is designed to provide
improved means whereby passing trains may themselves operate the signals to
indicate to a following train whether the line in advance thereof is or is not clear.
The said Invention is also designed to provide means whereby a train approaching
a signal will operate a sounding device, such as a whistle, bell, or the like if the
signal is at "danger" or "train on line," so that the driver may be warned by a
sound that the said signal is against him before he reaches or is in sight of the
latter, this sounding arrangement being chiefly designed for use during the existence
of fogs or snowstorms.
I carry my said Invention into practice as follows, that is to say, to the arm of
a semaphore signal I attach a chain or rod which is suitably connected with one
end of a lever, the other end of which lies close to one of the rails over which the
trains pass, and in such a position that the passage of a train will depress the
same. This lever is pivotted or fulcrummed near to the rail in such a manner that
the former has a short arm and a long arm, the former being the one against
which the wheels of passing vehicles press. To the end of the other arm the chain
or rod is connected as aforesaid, and near this end of the said arm I attach to the
same by means of a loose joint a pedestal or support having an extended or
widened base. This pedestal is designed to rest upon the ground and support the
long arm of the lever in its elevated position after the train bas passed, and thus
keep the signal-arm at "danger." In connection with the said pedestal I provide
a horizontal bar which is supported by a vertical post or rod, the latter passing
onl

page_text: through the said bar, the connection between the two being such that the bar can
readily move upon the rod or post. One end of the horizontal bar rests against
the aforesaid pedestal, and is attached to a chain, wire, or rod which is continued
along the lino in advance of the signal to such a point that when a train reaches
that point it will be safe to lower the signal to indicate "line clear" to a following
train. At this advanced point the chain, wire, or rod is suitably connected with a
lever pivotted near the rail, and so placed that a passing train will operate the
same and cause the horizontal bar to press forcibly against the pedestal and upset
the same, so that the lever to which the said pedestal is pivotted, being no longer
supported thereby, allows the signal arm to fall, in which position it remains until
another train passes and sets it again at "train on line" or "danger." The other
end of the horizontal bar is connected with a spring, which when the said bar is
released causes it to return to its normal position in order to operate again, as
before described.
It will be seen that by means of my Invention, as above described, a train on
passing a signal causes the latter to be automatically set to "danger" or "train on
line," and thus the said train is protected against a following one, and that when
the first train has travelled to such a distance as will render it safe to lower or
"take off" of the signal this is effected automatically by the train itself.
In order to give a sounding alarm to the driver in case a signal should be against
him, I provide at a suitable distance from the signal in the direction in which
trains approach the same an apparatus in which there is a collapsible bag or vessel
made of leather or other suitable material, the said bag being enclosed within a
suitable frame. Above this bag I provido a second bag, which when not distended
by air lies loosely at the top of the frame. The two bags communicato with each
other and with a chamber above the same, in which chamber there is a pipe
containing a whistle. At the lower part of the pipe there is a hinged valve which
is connected with a chain, wire, or rod, secured at its other end to the arm of the
signal in such a manner that when the said arm is elevated the valve uncovers the
pipe and covers an aperture in the chamber, and when the arm is depressed the
valve covers the pipe and uncovers the aperture in the chamber. A lever in
connection with this apparatus is pivotted near one of the rails in such a manner
that its short arm will be depressed by a passing train, thereby causing the long
arm to rise, which being under the lower collapsible bag will compress the latter
and force the air contained therein into the upper bag which will thus be distended;
and if the signal is elevated tho whistle will sound and warn the driver of a train
passing this apparatus that the signal in connection therewith is at "danger." If
this signal is down or at "line clear," the air forced into the upper bag by the
compression of the lower one will escape through the aperture in the chamber, for
the reason that, as above explained, the said aperture will be open and the pipe
closed, and thus no sound will be given.
Instead of a whistle to be sounded by the compression of air, I may employ any
other suitable sounding device so connected with the lever operated by the train
that the said device will be caused to operate by the passing of the train for the
purpose indicated.
The said sounding signal may be used either with or without the automatic
arrangement for operating the semaphore signals first herein described, and may
be adapted to any of the signals now in use.

page_text: SPECIFICATION in pursuanco of the conditions of the Letters Patent filed by
the said Thomas Murray Ford in the Great Seal Patent Office on the
2nd December 1881.
THOMAS MURRAY FORD, of Great St. Helen's, in the City of London, Shipowner.
"IMPROVEMENTS IN RAILWAY SIGNALLING APPARATUS."
"
My Invention relates to improvements in railway signalling apparatus, and is
designed to provide means whereby a train approaching a signal will operate a
sounding device or alarm, such as a whistle, siren, or the like, if the signal is at
danger," so that the driver will be warned or rendered cognisant of the fact that
the said signal is against him before he reaches or is in sight of the latter. The
said sounding device is especially designed to give an alarm during the existence
of fogs or snow-storms, and to replace the detonating signals heretofore used for
this purpose.
One method of carrying my Invention into practice is illustrated in the
accompanying Drawing, in which
Figure 1 is a plan representing the arrangement of my improved apparatus at
one side of a railway line; and
Figure 2 is an end elevation of the samo partly in section.
Figuro 3 is a vertical section on the line x, x, Figure 1, looking in the direction
of the arrow.
Figure 4 is an elevation drawn to an enlarged scale shewing the arrangement
below the whistle of a chamber, which is provided with a movable flap or door, for
the purpose hereinafter described; and
Figure 5 is a sectional view of the said chamber with the flap or door raised,
Like letters indicate the same parts throughout the Drawing.
In carrying my Invention into practice I arrange upon the inside of one of the
rails a in such a position that a train as it approaches the signal will pass over it
a plate or piece b, the upper surface of which is level or nearly level with the
upper surface of the rail; this piece b is attached to one end of a lover c. This
lever passes beneath the rail, and is pivotted in suitable bearings or supports d
adjacent to the said rail. The other end of the said lever is connected in any
convenient manner to the lower end of a collapsible bag or chamber e formed of
lenther, india-rubber, or other suitable material, and preferably enclosed within a
box, frame, or case f, which serves as a protection or covering to the said bag. To
the upper end of the latter I attach a whistle or other alarm g, which is sounded
whenever a train passes over the plate b, as hereinafter described.
The operation of the above described apparatus is as follows, that is to say :-
Assuming that a train is approaching a signal which is at danger the flange of
one of its foremost wheels will come in contact with the piece b, and depress the
short arm of the lever c, thereby causing its long arm to rise so as to compress the
collapsible bag e, and force the air contained therein into the whistle, thereby
sounding the same, and warning the driver of the train passing the said apparatus
that the signal in connection therewith is at danger.
In order however to prevent the sounding of the said whistle by the passage of
a train when the signal is set to safety or "line clear," I arrange below the whistle
or sounder a chamber g₁, which is provided with the flap or door h hinged to the
main portion of the said chamber at h', and suitably weighted to cause it to return
to the position shewn in Figure 4 when the signal is put to danger. To this flap
or door I attach an arm or lever i, which is united by a chain or other connection },

page_text: or by other suitable means with the wire or connection for operating the signal, so
that when the latter is set to safety or line clear the said flap will be raised into
the position shewn in Figure 5, and the air forced into the chamber below the
whistle or sound emitting device when the chamber e is collapsed will pass out
from the said chamber without producing an alarm. Or instead of providing the
whistle or sounder with the said flap or door I may connect the chain or wire from
the signal operating lever with the short arm of the lever c, so that when the said
signal is set to safety the said end of the lever will be depressed to such an extent
that the piece b will not be operated by the wheels of the passing vehicles. Or
instead of the means above described I may employ any other suitable devices,
whereby the sounding device will be rendered inoperative when the signal is set
to safety.
To prevent the giving of a series of alarms or sounds, which would be produced
providing the plate or piece b were depressed by cach succeeding wheel during the
passing of the train, I in some cases connect with the lever a two plates or pieces b,
which are arranged at a distance apart less than that between the axes of any two
of the wheels in the train, so that when the said lever is depressed by the contact
of the first wheel with one of the said plates b it cannot again rise until the entire
train has passed.
The return movement of the lever c to its normal position after the train has
passed is effected by the expansion of the collapsible bag or chamber c. If desired
however this return movement of the lever may be assisted by means of a weight
suitably arranged for the purpose.
To prevent the rupture or bursting of the aforesaid collapsible chamber or bag e,
which might occur in a sudden collapso of the same caused by the passage of a
wheel over the plate b, and the inability of the volume of air compressed in the
said bag to escape at a sufficient speed through the whistle or sounder, I prefer to
arrange above the said bag or chamber, and between the same and the whistle or
sounder, a second bag, which, when not distended by air, lies loosely upon the top
of the frame. The two bags communicate with each other, and are so arranged
that when the lever c is depressed by a passing train, and the bag e is therefore
collapsed, the air will be forced from the same into the second bag, which is
thereby distended, the air then flowing from the said bag through the whistle or
sounder.
•
In some cases I extend a pipo from the chamber e along the line in a forward
direction, and arrange the whistle or sounder at the end of the said pipe, so that
the alarm will be produced in advance of the driver when the first wheel of the
train passes over the plate b.
Although in the above description I have more particularly described n whistle
as the sound producing device it will be evident that I may employ in place of the
said whistle any other sound producing device through which air can be blown,
such as a siren, fog-horn, or similar instrument, or a devico known as a
"
screamer.
"
In some cases I arrange two whistles or sound producers and devices for forcing
air therethrough in connection with each signal, so that two successive alarms will
be produced during the approach of a train towards a signal if the latter is in tho
position to indicate danger.
Instead of employing the collapsible bag above described for forcing the air
through the sound producer I may use a cylinder with a piston adapted to bo
operated by the lover c, which cylinder is in communication with the said sound
producer.
Having thus fully described my said Invention, and the manner of performing
the same, I wish it understood that I claim,—
First. The employment for signalling purposes on railways of apparatus arranged
to be actuated by the wheel of a passing train or vehicle to produce a current or
pressure of air, and thereby blow a whistle or other like sounder.
Second. The combination with a whistle or other sound producing device of the

page_text: collapsible bag or bags and the pivotted lever, whose short arm is provided with
the plate adapted to be depressed by the flange of a wheel passing over the
adjacent rail, substantially as above set forth and for the purpose specified.
Third. The devices whereby the said whistle or other sound producer is rendered
inoperative when the signal is set to safety or "line-clear," substantially as abovo
set forth.
In witness whereof, I, the said Thomas Murray Ford, have hereunto set my
hand and seal, this Second day of December, in the year of our Lord One
thousand eight hundred and eighty one.
T. MURRAY FORD. (L.S.)