Improvements in Automatic Electric Signalling for Railways and Apparatus therefor.
Year: 1887

page_text: Date of Application, 11th Oct., 1887
Specification Accepted, 29th Nov., 1887
COMPLETE SPECIFICATION.
Improvements in Automatic Electric Signalling for Railways and
Apparatus therefor.
I, WALTER WALKER, of 5 Exchange Station, Liverpool, in the County of
Lancaster, 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 :-
My Invention relates to improvements on my system or method of automatic
electric signalling for railways, and apparatus therefor, for which I obtained Her
Majesty's Letters Patent No. 14,105 dated 2nd November 1886, and it has for
its object to simplify such system or method, to render the saine more economical,
and to provide a simple but efficient contact apparatus by which I now operate
the signals.
In the specification of the said Letters Patent, I described the use of local batteries
and mechanism or relays for use on single, or on double lines of railway, connected
with the contact apparatus which actuates the signals. Now, in carrying out my
present system or method, I dispense with the local relays and the local batteries and
circuits and couple the line wire of the main circuit directly with my improved
contact apparatus, hereinafter fully described, one main circuit relay being retained
to restore the earth connection after the passage of a train.
In the accompanying drawings, Fig. 1 shows a diagram of my improved system,
as applied to a line of railway over which trains pass in one direction only, while
Fig. 2 illustrates the same system as applied to a line of railway over which trains
pass in both directions.
Figures 3, 4, 5, 6, 7, and 8 shew my improved contact apparatus, as used in my
present simplified system, but which apparatus is equally applicable to the method
or system described in the specification of my former letters patent herein before
referred to.
Fig. 3 is a longitudinal section of the contact apparatus, Fig. 4 a cross section on
the line z, z of fig. 3, Figs. 5 and 6 are respectively a sectional elevation and a plan
of the contact proper, on an enlarged scale,

page_text: Now, in carrying out my present system or method I dispense, as already stated,
with one or two local relays and their local batteries, and connect the insulated wire
proceeding from the signal head or target directly to one of the terminals of my
improved contact apparatus, the other terminal being connected to earth.
Referring to Fig. 1, A, A, are the lines of rail, B is a signal head or target
exactly similar to that described in the said former specification, C is the insulated
line wire carried along the line from the signal, and D is an electric battery
interposed between two divisions of this wire. One end of the line wire C is
coupled to one end of the coils of the electro-magnet operating the signal, the
other end of these coils being coupled by another section of the same wire to
one of the terminals of one of the contact apparatus I, whose other terminal is
connected to earth. The distant end of the wire is coupled to one end of the
coils of an electro-magnet J, forming part of a relay F, the other end of such
coils being 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.
Fig. 2 illustrates, as above stated, the application of my improved system to a
line of railway over which trains have to pass in both directions. In this case
the contact apparatus N, Nx, are used at each end of the wire C, these ends
being connected to one terminal of each of these apparatus while the other
terminal, of the contact N, is connected to earth. Other contact apparatus N¹ N¹,
are also placed at each end of the section, and the insulated wire M, extends
from the one to the other, while being coupled on its way with a relay F, from
the electro-magnet J, of which, starts the second section of the wire C which,
after passing through a second signal head or target O, is finally connected to the
other terminal of the contact apparatus N*. This signal-head or target O, thus
placed upon the wire C, is arranged 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 lines of
rail. The signal-head or target B serves for trains passing on to the right hand end
of the line section, and the signal head or target O, for trains passing in an opposite
direction, as described in my former specification.
The working of this arrangement is as follows: the contact breakers N* N are
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 on to this section of the line, and
the signals fall, by gravity, to "danger" or "line blocked." Contact makers N', N',
actuated by a depressible bar T are also placed at each end of the section, as above
stated, so that a train, as it passes off from the section, either in one direction, or in
the other, causes the electric circuit to be completed through the wire C and the
signals to be set to "safety" or line clear."
66
My improved contact apparatus shewn in figures 3, 4, 5 and 6 (sheet III) consists
of a depressible rail or bar T, actuating a lever R, furnished at one end with a
counterweight R¹, (or spring) and enclosed in a rectangular metal box S, to one
extremity of which is bolted a hollow pillar or column P. The other end of this
weighted lever is jointed to one end of a vertical connecting rod r, placed in the
pillar, and whose other end is connected with the rod x, of the contact proper, by
means of an adjustable nut u. The lever pivots upon a supports fixed to the bottom
of the rectangular box S. The improved contact proper which is arranged in the
pillar or column P consists, as clearly shewn in figs. 3, 5, and 6, of a rod the
lower extremity of which is coupled, as above stated, with the connecting rod r of
the weighted lever, but insulated from it, while the upper extremity terminates in an
enlarged part carrying a screw upon which is fixed a brass piece ¹, and a piece of
wood z³, or any other suitable insulating material, the latter being screwed above, or
below, the brass piece according as the contact is to act as a circuit maker, or breaker.
This screw top of the rod is held tightly by a cluster of brass springs Y, with which
it establishes contact whenever its brass portion is lowered (or raised) so as to come
within the said springs, while, on the contrary, the contact is broken whenever the
insulated part is raised (or lowered) and comes within the said springs. The contact

page_text: is carried by a shelf t, cast or otherwise secured to the inside of the pillar P, and its
base plate 6, is insulated therefrom by a slab of vulcanite, or other insulating material.
Upon the said base plate 6 the springs Y are fixed by brass screws, and this plate
also carries two terminals or binding screws n, n¹.
In order to exclude water, or moisture, the pillar is provided with a cap Z, whose
flanges are bolted to those of the said pillar, a packing ring being interposed between
the flanges to form a tight joint (Figs. 3 and 5). A man hole p is provided so as to
allow access to the adjusting nut u.
The depressible bar T, and its two contacts, complete together a circuit, the first
contact which is operated upon by a passing train acting as a breaker of the circuit,
while the second and last contact, actuated by the train previous to passing off the
said depressible bar, acts as a maker, and and restores the earth connection by the aid
of the relay F, which relay, as before stated, is the only one now employed in the system.
The modes of connection of the depressible bar to to the contact apparatus, and the
operation of this apparatus by such bar, as shewn in figs. 7 and 8, are precisely similar
to those described in the Complete Specification filed by me on the 18th July 1887,
No. 10,056.
My improved system of automatic electric signalling for railways operates in the
following manner.
First, with reference to figs. 1 and 3, when a train passes on the line it depresses
the bar T, and with it the lever R, consequently the rods and are pulled down-
wards thereby bringing the top or insulated portion into contact with the brass
springs, and thus breaking the earth connection whereby the signal is brought to
"danger" by gravity. But as soon as the train has passed beyond the depressible
bar T, the lever returns, under the action of its counterweight (or spring) to its
normal position, thereby pushing the rods r and upwards so that the lower or brass
part thereof comes within the springs again, and is ready to re-establish the circuit
when the train in passing the maker at the other end of the section restores the earth
connection.
When the electric circuit through the wire C is broken by a train passing the
signal at the opposite end of the wire, the electro-magnet J, of the relay F, ceases to
attract its armature which 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 the wire M to one of the terminals of the contact
apparatus I. When the depressible bar T of the latter 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 attracts its armature and the earth connection is completed
through the latter 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."
"
"
With reference to Fig. 2, the contact breakers are 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 on to this section of the line and the signals fall by gravity to
Danger or "Line blocked." A contact maker actuated by a depressible bar, is
also placed at each end of the section, as above stated, so that a train as it passes off
from the section, either in one direction, or in the other, causes the electric circuit to
be completed through the wire C, and the signals to be set to "safety" or
" line clear."
Having now particularly described and ascertained the nature of this invention and
in what manner the same is to be performed I declare that what I claim is:
1. The improved method or system of automatic electric signalling for railways in
which the line wire, instead of being coupled to relays provided with local batteries,
is coupled directly to the contact apparatus, one main circuit relay only being
employed to restore the earth connection after the passage of the train, substantially
as hereinbefore described and shewn with reference to Figs. 1 and 2 of the drawings.

page_text: 2. The improved contact apparatus, having its parts arranged, combined, and
operating substantially as herein before described, and as shewn with reference to
fig. 3 of the drawings.
3. The construction of the contact proper herein before described, and shewn with
reference to figures 3, 5 and 6, of the drawings, in which a rod composed partly of
conducting material and partly of insulating material is arranged to be worked within
a cluster of metallic springs so as to complete or to interrupt the circuit as required,
and thus operate the signals.