IMPROVEMENTS IN ELECTRO-MAGNETIC RAILWAY SIGNALLING APPARATUS
Year: 1873

page_text: LETTERS PATENT to William Robinson, of Brooklyn, in the State
of New York, United States of America, for the Invention of
"IMPROVEMENTS IN ELECTRO-MAGNETIC RAILWAY SIGNALLING APPARATUS."
Sealed the 25th February 1873, and dated the 6th January 1873.

page_text: describes and ascertains the nature of the said Invention, and in what
manner the same is to be performed, in and by the following statement,
reference being had to the accompanying Drawings forming a part of this
Specification.
This Invention relates to mechanism actuated by electricity, by
which the approach of a railway train to a station, switch, drawbridge,
or other locality, is caused to automatically sound an alarm or display
a signal, to indicate the approach of the train, and its passage or
movement relative to the station or other point along the track.
The said Invention involves the operation of such signals by a circuit
controlled by the passage of the locomotive or carriages acting in
concert with track sections, disconnected from each other, and arranged
in connection with appropriate electro-magnetic appliances.
In one modification of the said Invention the several parts of the
apparatus are so provided that the circuit in its normal range is caused
to hold a visual signal out of sight until the wheels and axle, by
affording a diminished resistance to the passage of the current, change
the circuit and allow the signal to be brought into position for display;
also so that the changing of the circuit aforenamed in order to display
the visual signal may automatically sound a bell or other audible
signal; also so that the current, when the first-named circuit is normal,
will be divided between the said circuit and a secondary one, actuating
a signal at any desired distance in such a manner that when a less
resistance through the wheels and axle is offered than is afforded by
such secondary circuit, the distant signal will be released by the
cessation of the current through its actuating mechanism, thereby
indicating the arrival of the locomotive at, or its passage by, the known
point or place along the track section at which the aforesaid diminished
resistance affords the more facile passage to the current; also so that
by the operation of a "cut-out" or key the secondary circuit can be so
arranged with regard to the signal devices operated thereby, that by
providing a diminished resistance, the whole current will be diverted
through the circuit thus constituted, and by releasing the first-named
signal from the effect produced by the passage of the current through
its magnet, will cause the release and consequent display of such signal,
whereby the said signal may be actuated by the operator at the distant
point herein-1efore indicated. There is also employed in this modifica-

page_text: tion of the said apparatus a switch having its two rails insulated from
each other in order to prevent the completion of a circuit at any desired
places; also for use at drawbridges, a system of contact plates for
connecting the wires, and of fish bolts for connecting the rails, which
in the bridge and permanent way constitute essential portions of the
circuit; also for the attachment of the circuit wires to the rails a
metallic block or casting of a peculiar configuration.
Another modification of the said Invention comprises the combina-
tion of the conducting wires of a battery with rail sections separated
from each other, whereby the wheels of a locomotive or carriage
establishing metallic contact between the sections may be made to
close or break, as the case may be, the circuit that actuates the signal;
also the use in connection with the wires and separated rail sections
of a relay so constructed that when the current is passed through its
magnet the armative lever is actuated to change the current and render
it continuous through the said magnet for the purpose of maintaining
additional circuits in operation for the working of the signals, until such
time as the said magnet is demagnetised by "short circuiting" the
current and withdrawing the same from the magnet, which being
thus demagnetised, restores the circuit to its previous or normal
condition.
The said Invention also comprises a signal bell or audible signal
operated by axial magnetism, also the use of the stop chairs, and non-
conducting fish-plates, for the purpose of insuring the requisite per-
manent separation of the rail sections; also for the protection of the
batteries, signals, and other parts from cold or accident, or designed
injury, a signal house constructed with a subterranean chamber or
with double walls, enclosing between them air or other non-conductor
of heat.

page_text: Figure 22 is an elevation and partial vertical section of the improved
signal house, constituting one feature of this invention.
Figure 23 is a vertical transverse section showing a modified con-
struction of the same.
Figure 24 is a side view of a signal cupola arranged upon the said.
signal house.
Figures 25, 26, 27, and 28 illustrate methods of operating the signal
by axial magnetism.
In Figure 1 the track sections are composed of two paralled lines of
rails A laid in the usual manner for any ordinary or desired gauge, and
with the rails making up each line joined by fish-plates or otherwise,
in such manner that metallic continuity from end to end will be secured
in each line of rails aforesaid. Except as herein-after explained, the
paralled rails are practically insulated from each other. Each section is
furthermore insulated from the adjacent portions of the track at either
end as indicated at a, either by spaces or intervals destroying continuity,
or by the interposition of any suitable non-conducting material.
From one of the lines A of rails extends one wire 6 of an electric
battery B, the opposite wire c of which battery connects in like manner
with the other line of rails. From points. 6', c¹, at any desired dis-
tance the points of contact with the rails of the wires b, c, extend the
wires e, f, connecting with a relay magnet, at C. The circuit is thus
completed through the wires b, c, and e, f, and the contiguous portions
of the rails A, and while unbroken causes the relay magnet C to attract
and hold the armature D. The relay has attached to it one end of the
wire g leading to the electro-magnet E, the other wire h from this
electro-magnet connects to one pole of the secondary battery F, while
the opposite pole of the battery F connects by a wire i with the
armature D. The armature being brought to the position described
closes the circuit of the battery F through the electro-magnet E, and
causes the same to attract and hold the armature upon the vertical
lever G connected at its upper end by a cord, link, or chain to an arm m
on the rod I; the latter carries at one end the signal disc J, and at the
other the weight or counterpoise K, the lever itself being pivotted at n
to a standard L. The current being continuous through the circuit thus
constituted, and consequently. the armaturer of the lever G being.
brought forward toward the electro-magnet E, the action of the lever
'

page_text: will operate the rod I to depress the disc below the opening in the
signal house at or through which in signalling it is displayed.
Therefore when a locomotive or carriage passing upon the insulated
track section at any point at or about the locality indicated at a*, and
thereby through its wheels and axles offers a medium affording less
resistance to the current than the relay magnet O, the current forsakes
the said relay and follows the new circuit completed by the metallic
connection between the rail lines by the wheels and axles of the loco-
motives. The current being thus diverted from the relay C, the
armature D is withdrawn therefrom by a spring e¹, thereby breaking
the circuit from the secondary battery F through the electro-magnet E,
and releasing the armaturer of the lever G; the latter is drawn back
by the counterpoise or weight K, which by its reversed movement tilts the
rod I and lifts the signal disc J to display the same.
From the wire h of the secondary battery F extends a wire f* to an
electro-magnet or a helix at N, arranged in connection with appropriate
devices to sound a bell R by the closing of a circuit through such
magnet or helix. From the latter to a fixed metallic support at 611
extends the wire 9*. When the armature D is released from the
relay C, the spring e¹ draws it back against and in contact with the
support 6¹¹, thereby bringing the wire g* in connection with the wire i
of the battery F, and completing the circuit from the same through
the magnet or helix at N; therefore the same movement of the arma-
ture D, which by breaking the circuit through the electro-magnet E,
insures the display of the disc or visual signal J by closing the circuit
through the magnet or helix at N insures the sounding of the bell or
audible signal R.
At any desired distance from the apparatus just previously herein
described, say at or near the opposite end of the track section, may be
an office or signal station S, at which an electro-magnet T is arranged
for actuating a bell or audible signal U, and which connects the opposite
poles with the rail lines A by wires u, v. The said wires are provided
with a "cut-out" or key at B', whereby when desired they may be
detached from the magnet T and connected to each other without
contact with the said magnet. Normally however these wires com-
municate with the magnet.

page_text: The wires e, f, or those of the magnet C are of such diameter, and the
battery B is of such strength that only a portion, say one half more or
less, of the current passes through the circuit of which the said wires form
a portion, the remainder of the current passing through the continued
length of the rail section A and the wires u, v. The current through
the circuit thus formed actuates the magnet T, to draw to it and retain
an armature W, which by its position when thus brought against the
magnet keeps out of contact with the bell U, the striking or sounding
mechanism of the same. When however a locomotive or carriage passes
upon the rail section, and as herein-before set forth affords through its
wheels and axles a more ready conductor for the current, the latter is
diverted from the wires u, v, thereby demagnetizing the magnet T,
releasing the armature W, and allowing the sounding or striking
mechanism of the bell U to sound. When the locomotive has passed
from the rail section the current returns to and through the wires u, v,
again magnetizing the magnet T, and by drawing thereto the armature W
restores the bell to its normal condition. When desired a visual signal
may be substituted in lieu of the audible signal just herein set forth.
Assuming the signal disc J to occupy its normal position, dropped or
out of sight, it will in many cases be desirable to signal by the direct
volition of the attendant from the station S to a train approaching the
signal J. In such cases the "cut out" B' is operated to connect the
wires u, v, direct, or in other words without connection with the.
magnet T; the aforesaid wires being of sufficient size to afford a more
ready passage for the current than is offered by the wires of the relay
magnet C, the current is drawn away from the latter, thus demagnetizing
the relay C, and as a consequence displaying the disc J and also sounding
the bell R.
Where, as represented in Figure 2, a portion of the track section is
constituted by a switch it is essential that the insulation from each
other of the switch rails should be maintained, and to ensure this result
the switch bars o are so constituted that the rail sockets P at their ends
are insulated from each other. This insulation may be effected by
connecting the sockets by wrought-iron straps e to a central piece G of
wood, as in Figure 3, or by making the switch bar itself. of wood, with
the metal rail sockets secured thereto by bolts m³, as indicated in
Figure 4, or by constructing the switch bar of two parts having flanges
bolted fast together with insulating material * between them, and

page_text: wooden or other insulated thimbles, shewn in dotted lines at n', and
wooden washers o' so applied as to prevent metallic connection between
the two parts through the bolts, all as shewn in Figure 5; or instead
of either of these contrivances the switch bar may be of metal, its rail
sockets being furnished internally with a layer of non-conducting
material, preferably lined with metal as at 8", in Figure 6.
In Figure 7 is shewn a method of applying the principle of this
Invention to a drawbridge H turning around the point j. The
wires b, c, from the poles of the battery B* connect with insulated
metallic fixtures a². The rails A on the drawbridge have connected to
them two wires answering to those b, c, and terminating in spring
projections f, or equivalent devices projecting beyond the end of the
bridge. When the end of the bridge is closed the spring projections f
lap upon the fixtures a*, and connect the wires 6', c', and the other wires.
Further, when the bridge is thus closed the joints between the rails A
of the permanent way, and those on the bridge are connected by parallel
metallic fish bolts 9' so applied as to insure the ready passage of the
electric current from the one to the other. At any desired distance
from the drawbridge is the signal S' with its electro-magnets connected
by wires u', ', with the two rails of the rail section, thereby completing
the circuit. With the apparatus thus arranged the use of signal devices
as described with reference to Figure 1 will cause the visual signal to be
held out of sight until the breaking of the circuit by the turning of the
bridge. The passage of a locomotive upon the section, and the con-
nection thus established between the rail sections by diverting the
current from the electro-magnet at S* will also cause the operation of
the signal, thereby acting incidentally after the manner of a block signal
to give due warning to a following train that the track is obstructed, or
that there is other danger ahead.
Figure 8 shows the method of attaching the circuit wires to the rails.
A casting K is bolted against the web or flange of the rail, there being
preferably underneath and in contact with both rail and casting a flat
metal plate the better to insure metallic or conducting connection
between them. Formed centrally in the casting is a flat web a*,
with a vertical orifice or depression e through which is passed upward
the end of the wire to be fastened, the said end is then laid upon the
web and held thereto either by a spring catch c, by a fixed staple, by
soldering, or by other suitable means.

page_text: Referring to Figure 9, A indicates a road crossing over a double track
and having a signal house arranged in suitable proximity to the same,
as at B; C, is the battery with one wire a* connecting with one rail of
each track, and the other wire 6° connecting with the other or re-
maining rail of each track. From the wires a², 63, extend the wires a³, b³,
to the relay at c³, from which the signal at the house B' is actuated. A
locomotive or carriage approaching the crossing upon the section of
either track, by offering a less resistance through its wheels and axles to
the passage of the current will divert the same from the relay c³, and
thus operate the signal or signals at the signal house or station B² in the
manner herein-before set forth. It will be observed that in this mode of
applying the said Invention only two wires are carried from the signal
house to the tracks.
Figure 10 indicates the arrangement of parts when in block signalling
it is desired to set a safety signal in the rear of the train simultaneously
with the disappearance of the danger signal as described in Figure 1.
In this case the wire indicated at g* in Figure 1 is replaced by the
ground wire shown at g' in Figure 10, the wire ƒ* in Figure 1 by the
wire fin Figure 10, this wire f being extended back to the opposite
terminus of the track section or any desired distance in the direction
thereof, and there connecting with the safety signal magnet E' which
has its circuit completed by the ground wire 98. Thus it will be seen
that when a train has passed from the previous section it will not only
remove the danger signal at the end first reached of such section, but
will substitute in its place a safety signal shewing to any train in the
rear the passage of the locomotive or train to the section beyond. This
application is designed especially for double track roads. As arranged
on a single track line the passage of a train as from the left in
Figure 10 toward the locality of the signal actuated by the battery B
will set the signal at E as a danger signal, and at E' as a caution signal,
the latter being visible from the second track section in advance of the
moving train. By this means the engineers or attendants upon trains
approaching each other will be warned of such approach at a distance'
apart at least equal to the length of one section.
In carrying the second modification of my said Invention into
practice one of the lines of rails constituting the track should be
divided at those points where it is desired that the passing of the train
shall actuate the signal into sections separated from each other for a;
་

page_text: small but quite appreciable distance, say one fourth of an inch. The
rails may be kept at such distance apart by several devices which for all
the purposes of my Invention may
be considered the mechanical
equivalents of each other. For instance, as shewn in Figures 11
and 12, the end of each rail A° is bolted to a metallic stop chair
spiked to the ties or sleeper upon which the rail rests, or as shewn
in Figures 13 and 14, the rail joint may be fished with wooden fish
plates Co bolted through the rails, or if preferred one side of the rail
may be furnished with stop chairs and the other with a wooden fish
plate, as represented in Figure 15.
In Figure 16 I have shewn the carriage truck constructed with
metallic side frames B° bolted upon metallic journal boxes C, in which
play the journals of the wheels A°. The truck when astride of any of
the insulating joints just herein-before described as formed between the
several sections of the rail or track will establish metallic connection
between the two adjoining sections, and thereby complete an electric
circuit, of which the sections or any portion of the same may form a
part.
Referring to Figure 17, one of the rails of the track is divided
at aº, bº, cº, eº, f°, g°, hº, iº, k°, l°, into sections indicated respectively
at D°, E°, F°, Gº, Hº, Iº, Kº, L°, M°, N°, the poles of the battery 0°
connect by the wires mº, nº, with the sections E° and D°. From the
section I° to the section M° extends the wire tapping the wire 10° at
; R° is the automatic relay shewn in elevation in Figure 18, and
the magnets of which are indicated at S°. From the section K° extends
the wire 6° to the magnets of the relay whence the wire u° taps the
wire n°. From the section F extends the wire v° tapping at its opposite
end the wire 6°. From the separated metallic parts 10° of the relay
extend the two wires 2° of the secondary battery T°, these wires passing
around the magnets E³ which correspond to the magnet E in the
modification of my Invention first herein described and which actuates
the signalling devices. From the top of one of the stops 10°, over but
not normally in contact with the top of the other, projects a metallic
spring piece f*, which when depressed by the downward movement
caused by the attraction of the magnet S° of the armature lever W°
establishes metallic contact between the two posts and consequently
between the wires x°. The same movement of the armature lever by
elevating the opposite end brings the same in contact with the point yª

page_text: of the post he, which latter has the wire tapping the wire m°. From
the wire extends the wire * terminating in the section L°. The wire
m communicates with the section H° by a wire K*.
Assuming a train to move as from right to left, in Figure 17, upon
passing the division or divided joint c° the wheels of the locomotive or
carriages by establishing metallic contact between the sections E°, F°,
will complete the circuit through section E°, the wires mo, the battery 0°,
the wires u, the magnet S°, the wires 6° and 0°, and the section Fo.
The magnet S° being thereby magnetized attracts the armature lever
W to depress the one end of the same, which by depressing the spring
piece f* closes the circuit of the wires ° through the magnet E³ to
actuate the signal. Simultaneously with the closing of the circuit of
the wires as explained, the contact of the opposite end of the
armature lever with the point g' of the post he closes a circuit through
the said lever, the wire i, a portion of the wire m°, the battery 0°, a
portion of the wire n°, and the magnet S°. The establishment of this
new circuit causes the continued magnetization of the magnet 8° even
after the contact at co is broken, and consequently the continued
depression of the armature lever to complete the circuit through the
magnet Es and the continuous working or display of the signal by such
magnet.
The train having reached the crossing D° the wheels as when at c°
close the divided joint or interval 9°, thereby providing metallic contact
between the sections H°, I°, and completing a short circuit, offering less
resistance to the current than that just previously described; it with-
draws the current from the magnet S°, and by thus permitting the
reverse movement of the armature lever breaks the circuit through the
magnet E, and stops the signal actuated by the latter; the separation of
the armature lever from the point g of the post he leaves the magnet Sc
permanently demagnetised until such time as the train may reach
another closer. Assuming the train to be moving in the opposite
direction, the closing by the wheels of the joint between the sections
K°, L°, completes the circuit through the magnet So, which being thus
magnetized, continues magnetized to cause the working of the signal in
a manner identical with that already described until the train has
reached the crossing and demagnetized the magnet S° by bringing the
sections H° and I° into metallic contact, as already described.

page_text: In order that a train having passed the crossing may not by closing
the circuit at c° leave the signal in operation, I provide he relative
arrangement of the wires m°, n°, with the joint 6°, whereby when the
said joint is closed by the wheels a circuit is constituted affording less
resistance to the current than that through the magnet S°; the current is
thus withdrawn from the magnet and the magnet is at once demag-
netized after having been incidentally magnetized by the passage of the
wheels at c°. The wires 7° and, when the joint 4° is closed by the
wheels, secure a corresponding result when the train is running in the
other direction as from right to left in the Drawing.
In Figure 20 I have represented the signal bell actuated by axial
magnetism. The striker B* works longitudinally through the axis of the
helix C*, the wires of which, extended to the battery, are shown at 6*, c*,
the magnetization of the helix lifts the striker and brings it forcibly
against the bell D to sound the same. As represented in Figure 21
the striker B* is lifted by the helix and allowed to fall by its own
gravity against the bell in sounding. To provide for this dropping of
the striker and also to cause the intermittent sounding or interruption of
the bell, a portion of the circuit actuating the helix is constituted by a
spring e*, which by the upward movement of the striker is thrown out
of contact with the adjoining metallic surface of the circuit, thereby
breaking the circuit and releasing the striker from the operation of the
helix. The circuit is of course again completed when the spring is
allowed to resume its position by the descent of the striker, and the latter
is again lifted and so on in succession. In place of the interrupting
devices thus described other suitable contrivances may be employed for
the same purpose.
In Figure 25 I have illustrated a method of working the signal lever
by axial magnetism. The plunger Ex is drawn downward by the
magnetization of the helix F* through the axis of which it works. The
bar is connected by a strap g* with a pulley h* on the shaft or axle of
the lever G*; the latter is furnished at one end with a balance bob H*,
and at the other with a signal banner I. The downward movement of
the plunger of course lifts the banner to display the same.
A corre-
sponding arrangement is shewn in Figure 26, except that the banner is
shown in a position at right angles to that occupied by it in Figure 25.
In Figure 27 the strap from the plunger to the shaft of the signal
lever passes over an intermediate pulley i to multiply the motion

page_text: communicated to the aforesaid lever. It will be understood that the
movement of the plunger may, when desired, be made to move the signal
in a direction opposite that just above described.
In Figure 28, the signal is arranged upon a vertical shaft, a", bª, cª, are
pulleys; E is a magnet or helix, and D is a suitably arranged lever.
In climates where the cold of winter would be likely to injure the
batteries if they were left unprotected it is essential that the said
batteries should be guarded against freezing, and to this end the signal
house is constructed as represented in Figure 22. An excavation made
to any desired depth in the ground is lined with brickwork, stonework,
or simple cement x, and within the space thus provided is placed the
chamber y, of such external size that a space z is left between it and the
brickwork; this space may be maintained simply as an air space or may
be filled with sawdust or other equivalent non-conductor of heat. At
the top the inner chamber is closed with a trapdoor y*, and above
this may be another trap x* with a space z* between them; above is the
body L of the signal house, furnished with a door to afford access to the
interior and to the traps y*, **; the top is the signal box M*, in which
are placed the signalling devices, with wires connecting with the battery
enclosed within the chamber y, where, from the non-conducting character
of the walls and ceiling of such chamber, the battery is effectually pro-
tected from the action of frost. The signal box should be furnished with
suitable transparent shields capable of illumination for the protection
and better display of the signal disc.
When preferred the signal house represented in Figure 23 may be
used. In this the central chamber B™ is surrounded by a wall filled with.
any suitable, non-conducting material, between which wall and an outer.
one is an air space a". A door made non-conducting to heat affords
access through the side of the house to the inner chamber B, and upon
the house is placed the signal cupola A", shown in Figure 24.
For purposes of description the signal actuated as indicated in
Figure 1 has been herein set forth with reference to the working of this
system of signalling, but although this signal may be used when desired'
preference is given to one of those forms of construction and modes of
operation represented in Figures 15, 16, and 17, as being the best adapted
ordinarily to practical use; with reference to these last, instead of axial
magnetism being employed as the motive force, a force derived from an

page_text: electro-magnet of ordinary construction may be employed. The signal
magnet E (Figure 1) or other suitable magnet, or a helix used in lieu of
such magnet, may be attached directly without the intervention of a
relay to the rail sections in cases where such arrangement may be
deemed preferable.
Having thus fully described my said Invention, and the manner of
performing the same, I wish it understood that I claim,―
1st. The battery B and suitably arranged magnet in combination with
each other and with the rails of a section of railway track, whereby
when said section is bridged by the wheels and axle of a car the electric
circuit is charged and the signal operated through the demagnetization
of the said magnet, substantially as set forth.
2nd. Two or more signal actuating magnets or helices C¹, T, and a
battery B in combination with a rail section or sections A, whereby the
current is divided between the said magnets, substantially as and for the
purpose specified.
3rd. The combination of the signal actuating electro-magnet C, the
rail sections A, and the "cut-out" or key B, whereby the action of the
"cut-out" is caused to operate the aforesaid signal actuating magnet,
substantially and as for the purpose specified.
4th. The combination of the relay, of which the electro-magnet O
forms a part, with the two distinctive local circuits, substantially as
herein set forth.
5th. The switch bar made wholly or in part of non-conducting material,
whereby the switch rails are insulated from each other, substantially as
and for the purpose specified.
6th. The combination of the switch, constructed and operating as
described, with the metallic contact plate aº, substantially as and for the
purpose specified.
7th. The combination with the rails of the drawbridge and the circuit
connections of the battery B', of the fixtures a', and projections ƒ*, sub-
stantially as and for the purpose specified.
8th. The connection of a circuit wire to a rail forming part of the.
circuit, by means of the casting K*, constructed and applied substantially
as and for the purpose specified.

page_text: 9th. The apparatus arranged for signaling at crossings, substantially
as shown in Fig. 9.
10th. The apparatus arranged for block signaling, substantially as
shown in Fig. 10.
11th. The combination with the wires and seperated rail sections of a
relay so constructed that when the current is passed through its magnet
the armature magnet will be actuated to change the circuit and keep it
continuous through the said magnet for the purpose of maintaining its
own circuit or its own and additional circuits in operation for working
the signal until by directly breaking the circuit, or by short "circuiting"
the current, the magnet is demagnetized and the circuit restored to its
normal or previous condition, substantially as set forth.
12th. The signal bell actuated by axial magnetism in the manner
substantially as shown in Fig. 20.
13th. The signal bell actuated by axial magnetism and rendered
intermittent in its operation by means substantially as shown in Fig. 21.
14th. The several methods of actuating the signal lever by axial
magnetism shown in Figs. 25, 26, 27, and 28.
15th. The construction of signal houses for electric railway signals,
substantially as shown in Figs. 22, 23, and 24.
In witness whereof, I, the said William Robinson, have hereunto
set my hand and seal, this Twentieth day of November, One
thousand eight hundred and seventy-two.