Improvements in Block Signalling Apparatus for Railways.
Year: 1890

page_text: Date of Application, 2nd Sept., 1890--Accepted, 8th Nɔv., 1890
COMPLETE SPECIFICATION.
Improvements in Block Signalling Apparatus for Railways.
I, MAHLON SMITH CONLY, of 5459 Monroe Avenue, Hyde Park, Chicago, Illinois,
United States of America, Gentleman, 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:-
This invention relates to improvements in block signal systems especially designed
for use in connection with railways, in which elevated or tower signals are arranged
along the track at regular intervals, each pair constituting what is known as a
"block," and are automatically and simultaneously actuated so as to become visible
upon the train entering the block, and likewise simultaneously operated to become
invisible upon the same train leaving the block.
The prime object of this invention is to utilize the static discharge of one local
circuit, caused by the breaking thereof, for operating the instruments for controlling
the current through said circuit, and also through another corresponding local circuit
at the opposite end of the block, whereby upon the breaking of either local circuit.
the signalling devices contained in both of them will be operated so as to become
alternately visible and invisible.
Another object is to have a closed local circuit for each target or signal, but
connected with the adjacent target or signal in such manner that both of them
will be operated simultaneously by the action of a passing train upon the track
instruments accompanying each of the signals, and forming a part of each local
cirenit; whereby one of the signals may become inoperative without deranging the
whole system, or interfering with the continued and perfect operation of all of the
other signals in the systems.
A further object is to have the signals or targets actunted to become visible and
invisible by opposing electro-magnets included in the local circuit of each signal:
and to combine with the same, devices for alternately magnetizing and demagnetizing
said magnets, whereby they will becomo alternately active and idle so as to operate
upon the target in rotation, and when active will firmly hold the target in position by
force of magnetic attraction.
"
A still further object is to provide a tell-tale or "out of order," indication, distinct
from "safety," or 44
dangor," so that each signal will indicate when that particular
signal tower is not in working order, and not to be depended upon.
These objects are attained by the devices illustrated in the accompanying drawing,
in which
Fig. 1, represents in diagram a block signaling system embodying my invention as
applied to a single track railway, the two signals shown representing a pair of
signals locoted at the end of a single block. and with the targets up, or
invisible.
Fig. 2, a similar view of the same signals showing the targets down, or visible, and
the positions of the various parts of the signal changed accordingly.
Fig. 3, a plan view of the single track showing the disposition of the towers along
the same.
Fig. 4, a diagram view illustrating the application of my invention to a double track
system, showing three targets along one of the tracks.
Fig. 5. a plan view of a double track railway illustrating the disposition of the
towers along the same.
Fig. 6, an end elevation of one of the towers for supporting the signal.
Fig. 7, a side elevation thereof, also showing the location of the battery for the
local circuit.
Fig. 8, an enlarged elevation of the signal casing, showing a portion of the

page_text: mochanism.
Fig. 9, a vertical section thereof on the line 9, 9, of Fig. 8.
Fig. 10, a plan view showing the cap or covering of the casing removed.
Fig. 11, a detail elevation of the supporting post for the target and its
connections.
Fig. 12, a detail plan view of the base plite of the tower.
Similar letters of reference indicate the same parts in the sovoral figures of the
drawing.
It is a well recognised principle of electricity that whenever a closed battery circuit
is broken, a static discharge or secondary current is produced simultaneously there
with, of high electro-motive force, but small volume, whose tendency is to jump across
the break or opening, and which traverses the line or circuit in the same direction as
the primary current, and it is upon that principle that this invention depends for its
operation
My invention is equally applicable to either a single or double track system, and
when used in connection with the former, enables the throwing of a signal at the ends
of each block, to the front and rear of the same, simultaneously withdrawing, or
retulering invisible the signals previously thrown in the block last passed through;
when used in connection with the latter if embles the throwing of a signal at the end
of each block behind a train, which is all that is necessary, because all of the trains on
the same track move in the same direction, and simultaneously the withdrawing or
rendering invisible of the signal thrown at the rear end of the block last passel
through.
The mechanism or device in each case is the same, but as the circuits necessarily
differ, I will describe the two separately, beginning with the single track
system.
This in general consists of a series of visible signals of any suitable character, one
on each side of the track, as illustrated in Fig. 3, separated by about a mile, one of
each pair lying on the opposite side, but at the same point along the track with one
of the signals of the adjacent pair, so that the train in passing from one block to
another, will withdraw the signal from the block fast passed through, and
simultaneously, or nearly so, throw the pair of signals protecting the block just being
entered upon, which, by reason of their arrangement at opposite sides of the track,
shows a danger signal at the right of the track for other trains coming in either
direction.
Each signal tower of each pair of signals has its own local battery circuit, primarily
controlled by two track instruments for each post, which normally hold the circuits
closed by grounding, one the plus side, and the other the minus side of the battery :
the track instruments are so operated by the moving train as to momentarily open or
break the circuit at that point; the result of this temporary or momentary breaking
of the circuit by the track instruments causes a discharge of the static electricity
absorbed by the entire circuit either in the plus or minus direction, according to which
side of the local circuit is open.
The static discharge operating upon a polarized relay connected in the line, and
through branches connected with automatic switches for the local circuits for the pair
of signals, and also with the relay of the other signal of the pair, serves to short
circuit one or the other of two pairs of electro-magnets, arranged in opposition to each
other, in each of the local circuits. by grounding that portion of the local circuits, in
which the last operating electro-magnets are connector, thus giving practically all of
tho energy of the battery to the other pair of electro-magnets, which causes the target
of the signal to swing to the opposite direction; it will of course be understood that
these pairs of magnets are arranged to operate alternatoly, so that whenever a train
passes into the block protected by the pair of signals from either direction, both
siguals will be thrown or become visible, and that whenever the train leavos
the lock in either direction, both signals will be simultaneously withdrawn
from view.

page_text: Referring now more particularly to the apparatus which is common to both the
signals of the single and double track systemis, let A, represent a tower of any suitable
construction, resting upon a base B, at the ground, to which latter is secured a
casing, extending a suitable distance into the ground, and constituting a receptacle
for the local battery D, which may thus be placed below the frost line, an beyond
danger of freezing, the base being provided with a removable cover E, for convenience
of inserting and removing the battery.
Upon the top of the tower is support la casing, preferably circular in form, and
having two compartments, the lower one F, of which, is narrower when viewed in
cross-section, and is provided at one side of the centre with an opening C, extending
through both walls thereof, in which the target can be seen. This target H, works
between the walls of the lower portion of the casing, and may be of any suitable
character that will produce a visual signal, such for instance as a colored glass, in
contra-distinction to a white glass covering the opening G, and is suspended from an
arm I, pivoted at J, to a suitable post K, located in the upper chamber of the casing,
which latter is provided with a hinged lid or covering L, for affording ready access to
the devices located therein.
The arm I, is also connected by means of a link M, with an arm N, preferably
pendant, and extending radially from a rocking double armature O, pivotally supported
upon a suitable post P, secured to the casing.
Below this armature is located two pairs of electro-magnets Q. R. designed to
alternately attract the rocking armature, which is preferably composed of two
branches, upon which the magnets respectively operate. Thus it will be understood
that when one pair of magnets are energized so as to attract one side of the armature
and rock it in one direction, the target will be swung over so as to span and become
visible in the opening G, of the casing, and upon the other pair of magnets becoming
energized, and the first pair demagnetized, the armature will be rockol, and the
target swung in the opposite direction away from the opening G, and concealed behind
the solid walls of the casing so as to become invisible.
To the post K, are secured a pair of contact plates or springs S. T. between the
ends of which is located a contact point or block U, the said springs being arranged
at one side of, and in the path of movement of, so as to ho alternately operated by,
the free end V, of the arm I, of the target, so that when the target is operated in
either direction, one of the spring plates will be moved out of contact with the block U,
for the purpose hereinafter described.
In the upper chamber of the casing is also located a polarized relay W, the
armature X, of which, as more clearly illustrated in the diagram views, is provided
with a tongue Y for making and breaking contact between two insulated points, for a
purpose which will be described further on.
In practice it is preferred to have the framework of such a character that the
wires leading from the battery to the signal may be concealed from view, and protected
from the elements, to which end the frame may be of piping, through which the
wires may be strung, and which will also form a ground connection for the various
circuits.
As before stated, each target is equipped with all the devices previously described,
and the connection and arrangement of parts is alike in all signals, but the circuits
are arranged somewhat differently in the single and double track systems.
Referring now more particularly to the single track system illustrated in Figs. 1, 2,
and 3, the towers shown in the first two figures, represent a pair of towers, such for
instance as those indicated by a, and b, in Fig. 3, supposed to be upon opposite sides
of the track, and about a mile apart, the right hand one corresponding in position
with the tower shown in Figs. 7, to 10, inclusive, and therefore having the parts
thereof lettered the same as the parts in said figures, while the corresponding parts
in the left hand tower have the same letters marked "prime," for convenience of
description.
-Each tower has two track instruments, c, d, and e and, of any suitable character, by
which the action of the passing train will cause the contact points of the instruments

page_text: to separate, and thus break the circuit, it being understood that these points ne
normally in contact, and one of them always gr. undet through the wire g.
With the parts in position illustrated in Fig. 1, the ringets are invisible, the
openings, and C, slow "white," and indient that there is no train in the block
between the signals. We will now trace the primary sirenit bezinning with the
track instrument d, and following the heavy wires, which indicate the primary
circuit.
Wire 1, commeets the track instrument with the coils of the eletro-magnet R.
which in turn are connected by wire 2, with a contact point 3, which latter, with a
mate 1, are arranged to be alternately engaged by the armature tongue Y, of the
polarized relay W, which at this tim is in cont et with point . He the circuit
continues from point 3, by wire 5, to the pins side of the battery, the minus side of
which is connected by wire 6, with the point 4, themes through the armature tongite,
and by wire 7, to the ground.
The direction of flow of the current is indiented by the arrows in this target, and
also in the lett and target, in which the primary circuit is trace, through exactly
the same parts, which are there designated by the same characters with prime marks,
except that the position of the parts is rever, the current flowing from the battery
toward the track instrument of, which connects with the plus side of the battery D,
and toward the battery from the track instrument 1, which connects with the muris
side of the battery dª.”
Now, upon a train entering a block from either direction, it will pass over the
track instruments e, or without producing any result, eause one of them was
last actuated to place the parts in their prepo-ition, and can therefore have no
effect to change their po-ition: lait assuming that the train enters the block in the
direction indicated by the wied and arrow at the right of the drawing, as soon as it
pisses over the track in trament d, the primary circuit will be broken at that point
in the plus side of the circuit momentarily, and thoroby pro'nge an altro-stie
discharge, or what I will trm a "s con lary cieni," of the same sign which traverse-
the local circuit, in the same direction as the primary circuit.
But as the primary circuit is broken at the truck freut of, the static dischar_e,
which otherwise would jump nereas the break in the form of a spark, now passes
from the primary eirenit, into the secondary circuit proper, which will now be traced,
beginning with the wire 8, connecting with the primary wire 1, just beyond the
magnet R.
This wire connects with the spring contact plate T, and the circuit then continues
to the block U, through wire 9, to and through the relay coils W. through wire 10,
which constitutes the line to the relay coils W¼, of the other signal on the left,
through wire 9, to block 4, to contact plate T", and thence through wire s³, to the
ground, using a portion of the primary wire 1, and the track instrument " to
complete its circuit.
It will of course be understood that the passage of this current through all of the
connections described, is practically instantaneous, and that the effect thereof upon the
polarized relays, by reason of the direction in which it flows therethrougli. is to
attract the relay armatures to the opposite pole, causing the tongues Y, Y, to wing
over to the contact points 3, 3, and thus shunting the primary current from the
electro-magnet R, R, which are thus demagnetized, and at the same time diverting
the current through, so as to energize the electro-magnets Q, Q, which now attract
the rocking armatures 0, 0, and through the agency thereof, and the connections
before described, causes the targets H, H', to simultaneously swing over so as to
span the opening G, G, and thus cause the signals to show "red," indicating
danger, and that the track between the two signals is occupied.
The action of the inrgot in swinging over to the position described, also breaks
contact between the springs T, T, and the blocks V, VI, and permits the spring
contacts S, S', to move into contact with the blocks V, VI, and thus form a secondary
circuit.
The position which the parts assume at this time and retain during the time that

page_text: the train is within the block, is represented in Fig. 2, in which also the primary
circuit is indicated by the heavy lines, and the direction of flow of the current by the
arrows.
As the train continues to move, it will also pass over the track instrument e, without
having any effect, because the current is now shunted therefrom to the ground
through the armature tongue of the relay; but upon pissing over the track instru-
ment, at the other end of the block, the circuit through the magnet Q will be
temporarily broken, producing another static discharge or secondary current of the
sune sign as the last one describe 1, but which takes directly the opposite direction
through the line wire 10, and boil relay's coils, by reason of the changes in the
contact springs S, T, S, T, caused by the different position of the target lever :—
Thus,beginning at the junction of the wire 11', with the primary wire near magnet Q;
through wire 11, to S, and V, through wire 91, to and through relay coils W', and
back over the line wire 10, to the other relay magnet W, and thence by wire 9,
block U, contact springs S, and wire 11, to local circuit, thence to the ground, through
the track instrument e, to complete the circuit.
It will of course bo understood that the sign of the static discharge or secondary
current will depend upon which of the track instruments is employed for breaking the
primary circuits, which of course further depends upon the direction in which the
train enters the block; and that the breaking of the primary circuit on the plus side
of either battery will cause the static discharge to flow in one direction, while the
breaking of the primary circuit on the minus side of the same battery, will cause the
static discharge or secondary current to flow in the opposite direction, but the two
primary or local circuits are so arranged with rolation to each other, that the breaking
of the plus side of one battery, will have the same effect upon the relays, as the
breaking of the minus side of the other battery, and vice-rersa, and hence the track
instruments of the two local circuits are so arranged, that, regardless of the direction
in which the train is moving, it will always breik the primary circuits successively
on the same side of each battery, upon entering and leaving a block.
Referring now to the double track system illustrated in Figs. 4, and 5, it will be
seen that each of the signals is composed of the same elements, in the same relative
locations, and operating in the same manner as in the single track system; but as all
the trains upon each track always move in the same direction, it is unnecessary to
throw a signal to the front of a train, but only to the rear, for which reason, only one
line of signals for each track is employed.
These signals, like the signals of the single track system, work in pairs, but are so
connected that each signal successively forms one of two pairs of signals, co-operating
first with the next signal to the rear, so as to cause the latter to disappear when the
train leaves the block, and then co-operating with the next signals to the front, so as
to be caused thereby to disappear when the train leaves the block.
Thus, while the targets are shown in this drawing as coupled in serios, their
operation is that of independent pairs, each signal, as before stated, constituting one
of two pairs. but operates alternately therewith, that is to say, instead of both signals
being thrown, or both being withdrawn from sight simultaneously, as in the single
track system, one signal is thrown, and the other simultaneously withdrawn from sight
successively throughout the pairs of the series.
As a result of this difference in the operation of the two systems, the wiring or circuit
between the pairs of signals is necessarily different and rore simple. The reference
letters heretofore applied to the main elements, may be applied to the same parts in
Fig. 4. The primary circuit of each signal of this double track system is the same,
and may be readily traced by following the heavy lines, the arrows in the left hand
target representing the direction of the current when passing through the magnet R¹,
while the arrows in the middle signal represent the direction of the current when
flowing through the magnet Q.
It will be observed that there is only one track instrument for each tower, and that
each instrument is connected with the same side of the battery, which might be either
the positive or negative pole thereof.

page_text: Let the wheel between the first and savond towers on the left indicate the present
position of the frame, and the arrow the direction in which the train is moving, it
will be seen that the left hand signal target (?', is visible, indicating that the train is
between it and the next target at the other end of the block in the direction in which
the trains move on that track, that the armature tongue of the polarized relay W', in
on the left hand contact and is growled, and that the current at this time is flowing
through the electro-magnet R, energizing the same, and causing the signal to
appear.
The parts of the signal will remain in this position until the train passes over the
next track instrument, breaking the primary circuit therethrough and producing the
electro-static discharge, leaves the primiy wire proper at the point Q. Q. and
traverses the secondary circuit through the relay W, causing its armature longne to
swing over from the right to the left hand contact so as to divert the primary current
from the magnet Q, to the ungnet 1, after which it pass out over the line and lack
to the rear or left hand signal, and through the relay W', thereof, causing its armature
tongue to change from the left to the right hand contact point, and thus divert the
primary current from the magnet R', to the magnet Q, after which the static
discharge is groundet through the primary wire and track instrument of the left leani
magnet.
The effort of this neriou is to cause the target signal U, in become visible, or show
"red," in the opening of the central target, at which point the train is now, und
simultaneously the target 114, of the tower, to the rear, to lenua invisible. This
operation will be repeated throughout the system, each target siev cessively forming one
of a pair, with the targets at each side threof.
The third or right hand signal illustrates the operation of the tell-tale which is
equally applicable to both the single and double track systems, for indicating when a
break occurs in the primary circuit or when the battery fails to work, for any
cause, which tell-tale communicates the fact to the engineer by the target showing
half red in the opening in the tower, upon seeing which the engineer will proceed
with caution until the next tower is reach1.
This tell-tale is produced by having the contact springs S, T, of such a shape that
when neither of them is forced to the right or left by the target arm they will make
contact with each other, but not with the block C, each serving to hold the other ont
of contact with the block. In this manner, when both the magnets Q, I, become
demagnetized by the breaking of the primary circuit through them, or the failure of
the battery to work, the target will fill by gravity to a vertical position beneath its
supporting pivot, and the upper free end V, thereof, will stand between, without
touching either one of the contact springs S. T, but only the individual target whose
primary circuit is out of order, will be affected by such action, for the contact springs
will serve to complete the secondary circuit so as to bridge the disabled signal, and
thus the last signal operated will be caused to disappear or become invisible in the
usual manner, when the train reaches the next track instrument, the same as if the
idle tower did not exist.
Thus it will be seen that any tower whose local circuit may have become inoperative
from any cause, will be automatically switched out, and the line or secondary circuit
closed so as to bridge the idle tower, and hence the system as a whole does not become
deranged by the inoperativeness of any one or more of the towers, but romains
unaffected thereby, and perfectly operative.
This tell-tale serves to indicate immediately at exactly which point in the system
the battery or primary circuit of the system is out of order, and no testing is required
to locate the trouble thus effecting a great saving of time.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is
1. In a block signaling system, the combination with a series of signals, a pair of
opposing electro-magnets for operating each signal, and a local circuit therefor, of a

page_text: secondary circuit connecting each pair of signals, and a polarized relay for each signal
included in said secondary circuit for shunting the primary current of the local circuit
alternately through said electro-magnets, substantially as described.
2. In a block signaling system, the combination with a local circuit, a pair of
opposing electro-magnets for operating the signal included in said circuit, and a track
instrument also included in the circuit, of a shunting device operated by the breaking
of the circuit at the track instrument, for shunting the circuit alternately through said
magnet, substantially as described.
3. In a block signaling system, the combination with a series of signals, a local
circuit for each signal, a pair of opposing electro-magnets for operating said signals,
included in each local circuit, and a track instrument for each signal, also included in
each local circuit, of a series of secondary circuits connecting said signals in pairs, and
a polarized relay for each signal included in said secondary circuit, for alternately
shunting the local primary current through said electro-magnet, substantially as
described.
4. In a block signaling system, the combination with a series of signals, a local
circuit for each signal, a pair of opposing electro-magnets for operating the signals
included in the local circuits, and track instruments in each local circuit, of a series of
secondary circuits connecting the signals in pairs, a polarized relay for each signal,
included in said secondary circuit, for alternately shunting the local primary current
through said electro-magnets, and a switch device operated by each signal for changing
the direction of the current of the secondary circuit through said relays, substantially
as described.
5. In a block signaling system, the combination with a series of signals, the pivoted
targets thereof, a local circuit for each signal, and a pair of opposing electro-magnets
included in said circuits, of a rocking armature alternately attracted by said magnets,
and connected with, so as to operate the target, and a shunting device for shunting
the current of the local circuit alternately through said electro-magnets, substantially
as described.
6. In a block signaling system, the combination with a series of signals, the targets
thereof, a local circuit for each of said signals, a pair of opposing electro-magnets
included in each of said circuits, a rocking armature alternately attracted by said
magnets, and connected with, so as to actuate said targets, and a track instrument
included in each local circuit, of a series of secondary circuits connecting the signals
in pairs, and a polarized relay for each signal, included in said secondary circuits for
alternately shunting the current of the local circuit through said electro-magnets,
substantially as described.
7. In a block signaling system, the combination with a series of signals, the pivoted
targets thereof, a local circuit for each signal, a pair of opposing electro-magnets in
each circuit, a rocking armature therefor, alternately attracted by said magnets, and
connected with, so as to actuate the target, and a track instrument for each local
circuit, of a series of secondary circuits, connecting said signals in pairs, a polarized
relay for each signal included in said secondary circuits for alternately shunting the
primary current of the local circuits through the electro-magnets, and a switch device
operated by each target for changing the direction of the current of the secondary circuit
through the relays, substantially as described.
Dated this 4th day of Aust 1200
Witnesses:
R. (
OMOHUNDEO.
MAHLON SMITH CONLY.
A. M. BENNETT.
Haseltine, Lake & Co.,
45, Southampton Buildings, London, Agents for the Applicant.