An Improved Method of Automatic Electric Signalling for Railways, and Apparatus therefor.
Year: 1886

page_text: An Improved Method of Automatic Electric Signalling for Railways,
and Apparatus therefor.
I, WALTER WALKER, of Dashwood House, New Broad Street, in the City of
London, Engineer, do hereby declare the nature of this invention, and in what
manner the same is to be performed, to be particularly described and ascertained in
and by the following statement, reference being had to the accompanying drawings,
and to the letters and figures marked thereon, that is to say :-
"
This Invention relates to an improved method of automatic signalling for railways,
or "line
and apparatus therefor, whereby each of the signals used is held to "safety
clear," so long as an electric circuit is completed through the coils of an electro
"line blocked,"
magnet used for actuating that signal, and is changed to "danger" or
by the action of gravity, whenever the circuit through the coils is broken.
The signals are placed at intervals at the side of the line. The electro magnet of
each signal has one end of its coils coupled to an insulated wire carried forward along
the line away from the signal to any desired distance, and is there put to earth, in the
manner hereinafter described, the other end of the coil (at the signal end) is also put
to earth, as hereinafter described, and an electric battery is interposed at some point
in the length of the wire.
The mechanism, through which the earth connection is made at each end, is so
arranged that, as a train passes the signal, it momentarily breaks the earth connection
at that end, and thereby causes the earth connection, at the further end, to be likewise
broken, so soon as the electric circuit through the wire is broken, and the signal, con-
sequently, is no longer held to "safety," it is carried by gravity, to "danger."
is
When the train has passed the signal, the earth connection, at the signal end,
automatically again restored, but the earth connection, at the further end, remains
broken, until the train comes up to that end when it causes this second earth con-
nection to be also restored, so completing the electric circuit through the wire and
through the coils of the magnet, causing the magnet to shift the signal to "safety" or
"line clear."

page_text: The wire which is carried forward along the line, from each signal, is of such a
length as to be carried beyond one or more other signals, each of which has similarly
a wire carried forward from it and is worked in the same manner, so that, after the
passing of a train, there must always be one or more signals set to "danger" or "line
blocked," in rear of it.
With single lines of railway where trains have to pass over the line in both directions,
the apparatus, for momentarily breaking the earth connection, as a train passes on to
any section of the line, has to be placed at both ends of the wire which is carried
along that section, and a signal has also to be placed at each end of the wire, one signal
on one side of the line for trains going in one direction, and the other, on the opposite
side of the line, for trains going in the opposite direction, consequently, in whichever
way a train is going it will not only automatically set, say two or more signals to
danger," in its own rear, but will also set two or more signals to "danger" in front
of itself to block the line against any train passing in the opposite direction.
"
In the drawings, hereunto annexed, I have shewn ways in which it is preferred to
carry out the invention.
At Figure 1, I have shewn a diagram view of the mechanism for working one of
the signals on a line over which trains pass in one direction only.
In this figure A, are the lines of rail. B, is a signal head or target, such as herein-
after more fully described, provided with a lantern or lamp, C, the insulated wire
carried forward along the line from the signal,-D an electric battery interposed
between two divisions of this wire. One end of the wire C, is coupled to one end of
the coils of the electro-magnet used for working the signal, the other end of these coils
is coupled, by a wire, with the armature E, of an electro-magnet F; this armature is
ordinarily held by a spring against a contact pin G, which is connected to earth. One
end of the insulated wire coil of the electro-magnet F, is coupled to one pole of a
battery H, a wire from the other end of the coil, and another from the other pole of
the battery, are led to a contact apparatus by which they can be coupled together and
the battery circuit completed through them, whenever a moveable rail or bar I, which
is placed close alongside one of the line rails is depressed by the wheels of a train
passing over it. The contact apparatus may be of any ordinary construction, and
covered in to exclude moisture. When the battery circuit is so completed through
the coils of the magnet F, the magnet attracts the armature E, and draws it away
from the contact pin G, and thereby breaks the earth connection at the signal end of
the wire C, but as soon as the train has passed beyond the depressible bar I, the bar
again rises, so breaking the circuit of the battery H, the spring which acts upon the
armature E, then draws the armature against the contact pin G, and restores the
earth connection.
The distant end of the wire C, is coupled to one end of the coils of an electro
magnet J, the other end of the coils of this magnet is coupled to a contact pin K.
When the magnet attracts its armature, it holds it against the contact pin K, and the
armature being coupled to "earth," the "earth" connection for this end of the wire C,
is thereby completed.
When the electric circuit through the wire C, is broken, by a train passing the signal
at the opposite end of the wire, as above explained, the magnet J, ceases to attract its
armature, and the armature is drawn away from the contact pin K, by a spring, and
held against an insulated stop L, so breaking the "earth" connection at this end. To
restore the "earth" connection, when the train passes this end of the wire C, the
contact pin K, is coupled by a wire M, with contact mechanism, worked by a depressible
bar N, placed alongside of one of the line rails. When this bar is depressed, by a
passing train, the wire M is coupled to "earth," so completing the electric circuit
through the wire C, the magnet J then again attracts its armature and the "earth"
connection is completed through the armature, so that the circuit through the wire C,
remains complete after the train has passed, and the signal is consequently held to
safety" or "line clear."
68
At Figure 2, I have shewn a modification of the above plan, adopted for working
signals on a single line of railway over which trains have to pass in both directions,

page_text: In this case, the mechanism E, F, G, H and I, is.used as shewn at each end of the
wire C, so that the circuit, through this wire is broken by the passing of a train, in
either direction, onto this section of the line. A contact maker, and depressible bar N,
is also placed at each end of. the section, and the insulated wire M is continued from
the one to the other, in order that a train, as it passes off from the section, either
in the one direction, or the other, shall cause the electric circuit to be completed
through the wire C, and the signals set to "safety." A signal head or target O, is
also placed upon the wire C, at the opposite end of the wire to that at which the signal
head or target B, is placed, and also on the opposite side of the line of rails. The
signal heads or targets B, would be for trains passing on to the right hand end of the
section of the line, and the signal heads or targets Ŏ, for those passing on to the left
hand end of the section.
The depressible bars N and I, at each end of the section of line, along which the
wire C extends, must be at such a distance apart that a train passing over the line
must have passed beyond one of them before it passes over the other.
A modified way of automatically effecting the breaking or the completing of the
circuit through the wire C, is shewn at Figure 3.
In this arrangement, the armatures E, in place of being held by a spring up to a
contact pin G, are held up to this pin by the electro-magnet F, the local circuit
through the coils of which, from the small battery H, is always complete, except at
the times when a train is passing over the depressible bar I; the passing of a train
in this case breaks the local circuit instead of completing it.
In other respects, the arrangement is practically the same as that shewn at Figure 2,
and the parts are marked with the same letters of reference.
At branch lines or crossings, the requisite working of the signals for controlling the
passage of trains past the junction or crossing may be effected by any suitable contact
mechanism, worked either by hand, or automatically, as desired. For the signals, it is
preferred to use signal heads or targets, provided with any suitable lamp or lantern
which can be made to exhibit either a red or a white light, or a white or a green light,
according to the signal to be given; but semaphore or other form of signals might
be used.
The signal head or target, which it is preferred to use, is shewn at Figures 4 and 5.
Figure 4, is an elevation, and Figure 5 a plan view, both partly in section.
This signal head or target is so formed that the coloured disc used, swings in an
enclosed narrow chamber through which the light is projected, so that the disc is
effectually protected from injury, or from its movements being impeded.
A, is the narrow chamber with a lens B, at front, and a glazed opening C, at the
back, through which light can be projected from any lamp, placed upon the base D.
E is a disc of coloured glass, or red gelatine and mica or other suitable material
carried by a swinging arm F.
In one position of the arm, the disc comes behind the lens so that the light passing
from the lens is coloured, in the other position it is moved aside, so that a white light
issues from the lens.
The axis of the arm F, has upon it a short arm G, coupled by a link with one arm
of a bell crank H, the other arm of which is coupled, by another link, to an arm which
extends upwards from the armature I, of the electro-magnet J.
When the armature is not attracted by the magnet, the disc is brought, by gravity,
into the position in rear of the lens. When the armature is attracted, the disc is drawn
away to one side of the lens. The two positions are shewn in Figure 4.
Having now particularly described and ascertained the nature of my said invention
and in what manner the same is to be performed, I declare that what I claim is :-
1. The improved method, herein before described, of automatically operating railway
signals placed at intervals apart along the line, each signal being, when at safety, held
there by an electro-magnet through the coils of which an electric circuit from a battery
can be completed through an insulated wire which extends for some distance along
the line, and through carth connections, or their equivalent, at each end, such earth

page_text: connections being controlled by contact mechanism in such manner that when a train
enters on the section of the line along which the wire extends the earth connection at
that end is broken and the signal brought to "danger," by gravity, and remains at
danger," until the train, on passing off from the section of the line, again causes
the circuit to be completed and the signal thereby to be set to "safety" or
"line
clear."
"6
2. The means for automatically operating railway signals, substantially as herein
before described and illustrated in the drawings annexed.
3. The railway signal head or target having a swinging arm carrying a coloured
disc of glass, gelatine and mica, or other suitable material, mounted in an enclosed space
between the lens and a glass in rear of it, and acted upon by an electro magnet sub-
stantially as herein before described.
ERNEST DE PASS, Fel. Inst. P.A.,
68, Fleet Street, London,
Agent for the Applicant.