IMPROVEMENTS IN ELECTRO MAGNETIC SIGNAL APPARATUS FOR RAILWAYS AND IN THE MEANS TO ACTUATE THE SAME
Year: 1883

page_text: ETTERS PATENT to Frederick James Drewry of Burton on Trent in the
County of Stafford Gentleman Executor of William Morgan-Brown Patent
Agent of 38 Southampton Buildings London deceased for an Invention of
IMPROVEMENTS IN ELECTRO MAGNETIC SIGNAL APPARATUS FOR RAILWAYS AND
IN THE MEANS TO ACTUATE THE SAME Communicated to him by John
Dunckler Gould and Ben Morehouse Plumb of New York United States
and Granville Walter Daniels of Somerville Massachusetts United States of
America
די
COMPLETE SPECIFICATION filed by the said William Morgan-Brown at the
Office of the Commissioners of Patents on the 7th March 1883.
"
WILLIAM MORGAN-BROWN Patent Agent of 38 Southampton Buildings London
IMPROVEMENTS IN ELECTRO MAGNETIC SIGNAL APPARATUS FOR RAILWAYS AND IN
THE MEANS TO ACTUATE THE SAME "
Communicated to me by John Dunckler
Gould and Ben Morehouse Plumb of New York United States, and Granville.
Walter Daniels of Somerville Massachusetts United States of America
This invention relating to railway signals is embodied in a railway signal
apparatus of that class in which the signal is normally held concealed, or indicating
safety by the attraction of an electro magnet in a normally closed electric circuit
the said signal being actuated by some force, preferably gravity when the said
magnet is demagnetized and falling into position to be viewed by the engineer of
an approaching train, it then indicating danger, and the engine drivers being
instructed not to pass a point at which one of the said signals is displayed
By having the signal held at safety by the action of the electric current it will
be seen that it will indicate danger when the said current is interrupted from any
cause as the accidental or intentional breaking of a circuit.
The said signals are intended to be automatically operated by the trains, the road
being divided into a number of sections each guarded by a signal and having a
circuit controlling instrument operated by the train entering the section to break the
circuit and allow the signal to fall to the danger position thus preventing a succeeding
train from entering the said occupied section until the train which sets the signal
D

page_text: passes off the section, and by operating another circuit controlling instrument
causes the signal to be restored to its normal safety position. It is necessary for
operating a signal in this manner that the normally closed circuit shall be broken
by a train entering the section to set the signal to danger and that the said signal
shall remain so until the train has traversed the section, and shall then be restored
to safety when the train leaves the section. The instrument at the head of the
section operated by the train is usually a circuit breaker which remains open only
while the train is passing thus permitting the signal to fall as before mentioned
but the moment the train has passed the signal and while it is traversing the said
section the said circuit breaker is closed and it is essential that the said closure of
the circuit shall not restore the signal to its safety position.
This is accomplished in a great variety of ways which together with the
expedients for causing the apparatus to be restored to its normal position when the
train leaves the section form the subject of the present invention.
The invention consists in the combination of the following elements, the main
signal, an electro magnet and circuit controlling instrument operated by trains
entering the block section guarded by the said signal, an electro magnet and circuit
controlling instrument operated by the train leaving the said section, and a
secondary signal, the said main signal being controlled in its movements by each
of the said magnets in turn and the secondary signal being controlled only by the last
mentioned magnet.
Also in the combination with the main signal, of an electro magnet and its
circuit and normally closed circuit breaker operated by the train entering the
section and an electro-magnet, its circuit and normally closed circuit breaker and
means to open it when the train leaves the section the movements of the said
signal being controlled by each of the, said magnets in turn when the normal
condition of the said circuit breakers is changed upon the passage of a train.
Also in the main signal electro-magnet, and normally closed circuit breaker
opened by a passing train, combined with a second electro magnet which controls
the said main signal after the said circuit breaker is operated and a circuit
controlling instrument in the circuit of the said second magnet, the condition of
which is reversed while the train is passing it and a secondary signal controlled
wholly by the said second magnet and thus indicating the condition of the circuit
controlling instrument. Also in a signal combined with two electro magnets in
normally closed electric circuits respectively provided with circuit breaking
instruments at the entrance, and end of the block section, the said signal being'
moveable from control of one into control of the other of the said magnets upon
the opening of the instrument in circuit of the magnet at that moment controlling
the signal.
Also in a signal and two electro-magnets.combined with means to primarily
retract the signal from one of the said magnets towards, the other and a locking
device by which the said signal is retained thus partially retracted until engaged
and wholly retracted by the said magnet towards which it is moved.
Also in a signal and two electro magnets controlling. its movement from one to
the other position, the circuit of each of the said magnets being normally closed
when the signal is moving into.and retained in control thereof combined with a self
closing circuit breaker in circuit with one of the said magnets adapted to be held
open by the signal while under the control of the other magnet.
.
Also in a signal and electro inagnet by the attraction of which it
held in the
safety position, combined with a circuit breaker in circuit with the said magnet
adapted to be held open by the signal while in its danger position, and an indicating
electro magnet and signal in the said circuit whereby the condition of the main
signal is indicated.
Also in a signal and its two controlling electro magnets and circuit breaking
instruments in their respective circuits the said instrument remaining closed except
when positively held otherwise, combined with independent indicating electro
magnets and signals in each of the said circuits.
i

page_text: Also in a signal and its two controlling electro magnets and normally closed
circuit breakers in their respective circuits, combined with an electric switch in
circuit with both the said magneta.
Also in a signal its two controlling electro magnets and a locking device combined
with an electric switching apparatus in circuit with both the said magnets and
adapted in its movements to its normal position to first close both circuits then open
one of the said circuits and finally again close it, leaving both circuits complete at
the said switch.
Also in a signal arm provided with a projection and signal hung thereon to swing
as a pendulum under the action of gravity combined with a pivotal locking device
having its engaging portion. in the path of the said projection whereby when the
said signal makes less than a complete oscillation the said projection is engaged and
prevented from return movement by the said. locking device, but when it makes a
complete oscillation it passes out of engagement with the said locking device and is
permitted to make a return movement.
Also in a signal and the electro magnet by which it is controlled, combined with
two independent batteries both normally in circuit with the said magnet but acting
in opposition to one another and a circuit constrolling instrument for one of the
said batteries automatically operated by the passing train whereby the said battery
may be removed from the circuit of the said magnet or have its polarity reversed
therein leaving the other battery to act unopposed or assisted upon the said signal
controlling electro magnet.
Also in a railway signal apparatus, the combination of the signals, their
actuating magnets, and circuit therethrough with independent actuating batteries
normally in circuit with the said magnets and opposed to one another and corre
sponding independent circuit changing instruments at each end of the block section
automatically actuated by the train by means of which the battery at either end of
the section may be made to act unopposed by that at the other end.
Also in a signal and electro magnet and its armature to operate it, combined
with a normally closed circuit through the said magnet and generator therein of
sufficient power to cause the magnet to hold the said armature when attracted, but
insufficient to move it when retracted, and an actuating battery normally inactive in
the said circuit and the circuit controlling instrument therefor operated by the train
in passing, by which the said battery may be caused to act in the said circuit.
Also in a signal and electro magnet and armature by which it is actuated,
combined with two batteries normally set in opposition in the circuit of the said
magnet and an electric switch by means of which the conductor joining one pair
of like poles of the said batteries may be connected with the conductor or ground
joining the other pair of like poles, and an independent circuit thus formed for each
battery in which it acts unopposed.
Also in a signal actuating electro magnet, and armature and circuit through the
said magnet connected with one portion of a circuit controlling instrument, the
other portion of which is connected with the ground or other terminal of the circuit
combined with a battery having its two poles respectively connected with the two
portions of the said instrument when in its normal position, the said poles also
being connected with contact points by which the said poles are connected in the
inverse order with the same portions of the said instrument when moved from its
normal position.
Also in a signal operating electro magnet and divided battery and circuit breaker
in circuit therewith, combined with a pole changing device operated by the said
signal in its movement which takes place when the circuit is broken whereby the
position of one portion of the said battery in the said circuit is reversed and it
operates to neutralize the current of the other portion.
Also in a signal operating electro magnet, divided battery in circuit therewith
and pole changing device for one portion of the said battery operated by the signal
combined with a circuit between the two portions of the said battery, and a circuit
controlling device therein, whereby one portion of the battery is caused to act

page_text: independently and its polarity is changed in the consequent movement of the
signal.
The signal operating electro magnet and divided battery and normally closed
circuit breaker in circuit therewith, combined with a pole reversing device for one
portion of the said battery operated by the said signal in its movements caused by
the said magnet, and normally open branch circuit and circuit closer therein
between the two portions of the battery.
Also in a signal actuating electro magnet and divided actuating battery in
circuit therewith, combined with a pole reversing device for one portion of the said
battery operated by the said signal whereby when the signal is in one position the
two portions of the battery are opposed to one another and when in the other
position they act in conjunction.
Also in a signal operating electro magnet, divided battery in circuit therewith
and pole changing device for one portion of the said battery operated by the said
signal in its movements, combined with an electric switch in the said circuit and
a branch circuit for the said portion of the battery having an anvil or contact
piece engaged by the said switch in its movement by which the main circuit is closed.
Also in a railway signal apparatus the signal-actuating magnet in a normally
closed circuit, combined with a circuit breaker and relay or circuit changing
magnet in the said circuit and resistance interposed and retained therein by the
said relay when the said circuit is broken and subsequently closed.
Also in a signal operating electro magnet, and relay, combined with branch
circuits from the said signal operating magnet of different resistance controlled by
the armature of the said relay.
Also in a signal actuating magnet relay, and resistance interposed in the circuit
of the said magnet by the said relay, combined with an independent circuit and
closer, including the said signal actuating magnet and battery without the said
resistance.
Also in an electro magnet and pole changer controlled by it combined with the
polarized relay and resistance controlled by it in accordance with the condition of
the said pole changer and its controlling magnet.
Also in an electro magnet and pole changer controlled thereby, and a polarized
relay controlled by the said pole changer, combined with resistance interposed by
the said relay when the pole changer is reversed by the demagnitization of its
controlling magnet, and an independent branch circuit and circuit closer between-
the said magnet with its battery, and the resistance, whereby the magnet is caused
to attract its armature and thus cause the pole changer and polarized relay to be
restored to their normal condition and the resistance removed from the circuit.
Also in a railway signal apparatus the electro magnet having two coils in
independent circuits, combined with the pole changing device in one of the said
circuits opérated by the armature of the said magnet.
Also in the combination of the electro magnet having two coils in independent
circuits, the circuit breaker by which both said circuits are broken at the saine
time and the electro-magnet demagnetized, and the pole changer in one of the said
circuits operated by the armature of the said magnet whereby after the movement
of the said armature from the poles of its magnet, the current in the said circuit is
made to act in opposition to the current in the other circuit. on the cores of the
said magnet.
J
Also in the combination of the electro magnet having coils in two independent
circuits, the pole changing device in one of the said circuits operated by the
armature of the said magnet whereby in the movement of the armature from the
poles of its magnet, the current controlled by it is set in opposition to that in the
other coil of the said magnet, and a circuit breaker in one of the said circuits only;
operated by trains passing off from the section whereby the magnet is acted upon
by the unopposed current in the unbroken circuit, its armature attracted thereby,
and the pole changing device restored to the position in which both currents act in
conjunction, when the circuits are both closed.
:
'

page_text: Also in an electro magnet having two coils in independent circuits, combined
with a pole changing device operated by the armature thereof in one of the said
circuits and an electric switch having mechanically connected arms, one for
controlling each circuit, and provided with an extended contact for one of the said
arms whereby in closing the said switch, one of the said circuits is closed before
the other.
Also in the combination of the electro magnet having two coils in independent
circuits, the pole changing device for one of the said circuits, operated by the
armature of the said magnet, the circuit breaker operated by trains entering the
block section by which both circuits are opened at the same time, and the circuit
breaker operated by trains leaving the section by which one circuit only is opened.
Also in the combination with the signal actuating electro magnets of a switch
operating electro magnet and resistance interposed in the circuit of the said switch
operating magnet by the movement of its armature when retracted upon the
opening of the circuit, whereby the said armature is retained retracted after the
subsequent closure of the said circuit.
I
Also in a main signal controlling electric circuit and switch operating electro
magnet therein, combined with resistance in two portions, one located near each
end of the section one of the said portions being interposed in the said circuit by
the armature of the said magnet when retracted, and a branch circuit between one
portion of the said resistance on the one side and the battery with the said magnet
on the other side whereby the said battery is caused to act upon the said magnet
unaffected by the said resistance when the said branch circuit is closed.
Also in the main signal controlling electric circuit and two switch operating
electro magnets therein-combined with resistance one portion of which is introduced
into the circuit by the armature of each of the said magnets when retracted, the
said resistance and magnets being adjusted as described whereby when the entire
resistance is in circuit, the said armature remains retracted, but when either
portion of the said resistance is removed the said 'armatures are attracted and thus
remove the entire resistance.
Also in the combination of the signal actuating magnets, the switch magnets and
resistance interposed in circuit thereby the circuit breakers, and branch circuits and
circuit closers therein, whereby the said resistance is removed from the circuit of
the said switch magnets and is retained thus removed by their consequent
operation.
Figure 1 is a front elevation of a signal apparatus such as may be employed in
carrying out this invention.
r
Figures 2 and 3 enlarged details thereof to be referred to.
Figures 4 and 5 diagrams of the circuit employed in connection with such a
signal apparatus when applied to double and single track roads respectively, the
signals in the former case having to indicate for trains coming in one direction only,
while in the latter case or on single track road the signals have to indicate at both
ends of each block section simultaneously to guard both the front and rear of the
trains from collision.
Figure 6 illustrates the form of circuit controlling instrument that may be
employed, it being automatically operated by the train to produce any desired
change in one or more circuits.
Figure 7 indicates in diagram a somewhat different construction of the signal
apparatus from that shown in Figure 1, and the different arrangement of circuits,
batteries and instruments for controlling it.
"
Figure 8 illustrates in diagram a circuit' operating on a similar principle to that
shown in Figure 7 but differing slightly therefrom and;
Figure 9 is still another modification of the same general plan.
Figure 10 illustrates another plan of operation and.
Figures 11. 12; are details of pole reversing instruments employed in the said
plan,
:
:

page_text: :
Figures. 13. 14. 15. and 16' illustrate other plans for accomplishing the same
result.
Figure 17 is a diagram showing the arrangement of signals when applied to a
signal track road, and Figure 18 a modification to be referred to. "
The signal and its actuating mechanism shewn in Figures 1 to 7 is contained in
a case A provided with an opening O through which the signals are displayed to
indicate danger they being retained aside of the said opening when the block
section guarded by them is unoccupied and safe for a train to enter.
[
The main signal a. shown as the usual red disc or target is mounted on a rod b
pivoted at Qin such manner that the signal will vibrate from the position shewn
in full lines aside from the opening into the position in line with the said
opening under the action of gravity, it operating when constructed as shown in
Figure 1, like a pendulum. The rod b. is provided with an armature c. which is
acted upon by a magnet M to draw the signal towards and retain it in the position
shown in full lines Figure. 1, this condition indicating safety and the magnet M
being therein called the main or safety magnet as it normally acts on its armature and
retains the signal at safety when the track is in its normal position or unoccupied
and safe for a train to enter on it.
}
Another magnet M' is arranged to operate on an armature c¹. or on the opposite
side of the armature c. the attraction of the said magnet M¹ tending to move the
signal a. towards and retain it in the position shewn in dotted lines Figure 1 where
it can be seen through the opening O. and indicates danger.
The signal a with its arm b. and armatures c. c. is primarily retracted from either
magnet M. M by the action of gravity which however only partially effects the
retracted movement and the two magnets thus arranged each operates as an
auxiliary retractor, for the other by which the movement of the signal is completed
and the armature is wholly removed from the control of the magnet from which it
is thus retracted.
'
The magnet M' is provided with a second armature d mounted on an arm e,
pivotted at 3 and provided with a signal disk a¹. which is preferably of a different
color from the one a. and so shaped that when both are in line with the opening Othe
disc a'. being between the said opening and the disc a, the latter will show behind the
disc a'. through the opening a 2. therein or, if desired the signal a¹ may be square
or of less area than the one a. When the armature d. is not held by the magnet M',
the arm e, and disk a¹. move by the action of gravity into line with the opening O,
and when the magnet M¹ is demagnetized the signal a. will usually be under
control of or held by the magnet M so that the signal a¹, will be displayed and the
signal a concealed. The circuits employed with the apparatus thus far described
and illustrated in Figures 1 and 2, are shewn in Figures 4 and 5, that portion of the
circuit belonging only to the magnet M being shewn in the finest lines, that belonging
only to the magnet M¹ being shewn in heavier lines, and that belonging to the both
magnets being shewn by the heaviest line.
The diagram Figure 4 represents the signal as applied to a block section of one
track of a double track road over which the trains pass always in the same
direction.
The main battery B has one pole connected at 10. with the main line wire L
which includes the coils of the magnet M and also includes a circuit breaker f 80
constructed as to retain the line L normally. closed but adapted to break it by the
action of the train when passing into the section. The said line L is connected at 12
with the return wire L' connected at 13, with the other pole of the battery B.
The circuit controlling instruments that are to be automatically operated by
the train may be of any well known construction, numerous forms having been
successfully employed.
n'armature
One form is illustrated on a larger scale in Figure 6, it consisting of an
lever f. having one or more contact points f*. controlled by the movement of the
said lever after the manner of a common telegraph relay, the said armature lever
being actuated by an electro magnet f*. included in a local circuit ƒ6. fƒ³. including

page_text: t
a battery fo. and terminating in the opposite rails f. f10. of a short section of the
railway track insulated from the remaining portion of the said track.
The circuit f. f. is shewn as normally open between the rails fº. f10. and the
magnet consequently demagnetized and the armature lever f³. retracted by the
action of the spring f".
As soon however as a train passes over the rails fº. f10 the wheels and axles
form a metallic connection between the said rails completing the circuit of the
battery f. and magnet f. and thus causing the armature f³ to be attracted and
its contact with the stop f. to be broken thus breaking the circuit, the terminals
of which are connected with the said lever f³. and stop f. respectively.
'
It is obvious that an instrument of this construction can be employed to close a
circuit one terminal of which might be connected with the lever f. and the other
with a front stop. f12, therefore, or that any desired change in one or more circuits
can be made by a proper construction of the said armature lever and its front and
back contact points.
Referring back to Figure 4. the battery B, has one pole connected at 10 with the
wire L'including the coils of the magnet M' and also including a circuit breaker f',
similar to the one f but located at the end of a block section which is spanned by
the said wire L' and adapted to be broken by the action of the train leaving the
said section.
T
When a train moving in the direction of the arrow operates the circuit breaker f,
the signals a. a. being in the position shown in full lines Figure 1, it opens the
circuit of the magnet M which thus releases the armature c and permits the signal a,
to swing into the position in line with the opening where the armature c'. is
attracted and held by the magnet M. M¹.
'
The circuit of the magnet M is closed immediately after the train passes over the
insulated rails f. f10. at the entrance of the section but owing to the remoteness
of the armature c. from the poles of the said magnet M it is unable to withdraw the
said armature and connected signal arm from the control of, the magnet,M¹ and the
signal a. is consequently retained displayed through the opening O' while, the traini
is traversing the section of track between the circuit breakers f. 'f¹. and any
succeeding train will be warned not to enter the section..
When the said train which has passed the circuit breaker f and set the signal a.
at danger arrives at the circuit breaker f¹. it breaks the circuit L' of the magnet M²,
which thus releases the armature c. and permits the signal a. to return to the
safety position shown in full lines Figure 1, and at the same time, it releases the
armature d. and permits the signal a¹ to move under the action of gravity into
position to be displayed through the opening O as long as the train is passing over
the insulated rails ƒ ƒ10. connected with the circuit breaker f' so that although
the signal a returns to safety when the first wheel of the train operates the circuit
breaker f¹, the signal a'. will remain displayed until the last wheel has passed
over the said rails and the train is entirely clear of the section.
A train should not be permitted to pass the circuit breaker f until both
signals a. a. are concealed but it will be seen that if a train should pass the
circuit breaker f while the signal a¹. was displayed or in other words while a
preceding train was passing over a circuit breaker f¹ the second train might
wholly pass the circuit breaker f before the first train had passed the circuit
breaker f. so that the magnet M would again be charged before the magnet M'
and the signal a thus restored to the safety position while the second train was.in
the section. This would be prevented by a proper regard for the indication of the
signal a¹, but such a false safety signal for the second train is also prevented by
means of the locking device g best shown in Figure 3 which is arranged to engage
a projection h on the arm b of the signal a. and hold the latter in its danger
position even though the armature c¹. is not held by the attraction of the
magnet M¹.
The locking device g. is pivoted at 5, and properly weighted or acted upon by a
spring, to normally hang or remain in the position shown in full lines Figure 3,

page_text: where its upper edge 6. lies in the path of the projection h on the signal arm b.
as the latter with the signal a passes from the safety to the danger position.
As a pendulum in swinging under the action of gravity does not rise so far
above its lowest position as the point from which it started the signal a when
swinging from its safety position unassisted by the attraction of the magnet M¹.
will not move wholly to the position shown in dotted lines Figure 1 or full lines
Figure 3 but will stop somewhat short of such position as shown in dotted lines
Figure 3.
h
In this movement the projection h engaging the upper edge 6 of the locking
device h will move it to the position shown in dotted lines Figure 3 in which the
said locking device acting upon the projection h. will effectually resist the movement
of the signal arm d from the danger towards the safety position but will not
prevent its movement towards the danger position which will take place as soon as
the magnet m¹is again magnetized. When the said signal arm d. is moved wholly
over to the danger position as shewn in full lines Figure 3 the projection / passes
beyond and disengages the upper edge 6 of the locking device g. permitting the
latter to return to its normal position shewn in full lines so that the projection h
in the return movement of the arm b from the danger to the safety position will
not engage the top of the said locking device but will engage the side thereof, so
that the said device, will turn freely on its pivot 5 affording but little resistance
to the movement of the arm b.
It will be seen that as far as the operation of the main signal a is concerned,
that one of the magnets M. M. which is not acting upon the said signal might have
its circuit broken, and in case separate batteries and circuits were employed for
the two magnets, the battery power might be saved by employing a circuit
breaker for either magnet which should be open while the signal was held by the
other magnet.
Such a circuit breaker is shewn at i. in the circuit of the magnet M. it being
opened by the action of the signal arm d. see Figure 1 when the latter is in the
danger position, either held by the magnet M¹ or the locking device g.
The said circuit breaker thus serves to indicate the condition of the main signal
at other desired points in the circuit.
For instance as shown in Figure 4, the circuit L of the magnet M contains an
electro magnet M. which in acting upon a signal a. shows when the said circuit
is opened or closed and consequently indicates whether the main signal is at safety
or danger.
A magnet M³ is also shown in the circuit L' of the magnet M¹ controlling a
signal a which indicates the condition of the circuit of the magnet M¹. These
indicating signals a.. a. or the ones a³. alone will be employed at switches draw
bridges or other places in the section of track were the said track is liable to be 4
made discontinuous at times and they will indicate when the main signal has been
set to danger by a train entering the track section and operating the instrumentƒ
and i so that the operator at the switch or draw bridge will be warned not to
open such switch or drawbridge or disturb the track while the train is approaching.
When desired to disturb the continuity of the track as by opening the switch or 4
drawbridge the signal a. at the end of the section can be set to danger by opening
the circuit L of the magnet M or the signal a¹. can be set without disturbing the
signal a. by opening the circuit L'. of the magnet m¹. or preferably both signals a
and a¹ will be set by opening the portion L2. of the circuit which is common to
both magnets as shewn by the electric switch S, Figure 4, the said switch S may 5
be connected with the moveable operating mechanism for moving the rail or draw
bridge bolt so as to be automatically operated before the track is disturbed, and it
is preferable to use in addition to a switch thus automatically actuated another
band operated electric switch so that the signal can be retained at danger. during
the various operations of shifting cars without changing the position of the said 5
signal at each change of condition of the rail.
When both circuits are thus broken the signal a¹. will be retained displayed by

page_text: the action of gravity and the signal a. by the locking device g and it will be seen
that if both circuits were closed simultaneously once for all the signal a. would be
caught by the nearer magnet M' and thus retained in the danger position.
In order to prevent the signal a from being thus placed or left in the danger
position when the switch S, is returned to its normal position closing the circuit L³.
of both magnets an additional switch S¹. mechanically connected with the one S;
is employed the said switch S¹ controlling the circuit L of the magnet M' alone as
follows: The switch S¹ is provided with two buttons or anvil pieces 7. 8. as
shown, it moving across the space between them when the circuit Lis broken by
the switch S to set the signals to danger and the switch S is provided with a long
anvil piece 9 from which it is moved to open the circuit of both magnets.
By this arrangement the switches S. S¹. when moved from the full to the dotted
line position Figure 4 but the signals a, a'. to danger the switch S', will first
break the circuit of the magnet M M¹ which will have no effect upon the main
signal a. as it is then controlled by the magnet M. and when the switch S. bas
passed entirely off from its anvil piece 9 the circuits of both magnets M. M will be
broken simultaneously and the main signal a will be caught in its danger position
by the locking device g as before described.
In the return movement of the switch S. S¹. both circuits will first be closed by.
the corresponding anvil pieces 8. 9. when the magnet M¹ will attract the armature c';
and thus disengage the signal arm b. from the locking device g, the circuit of the
magnet M being then connected at the switch S. although it is still open at i.
In the further movement of the switches S. S¹. the switch S. passing between its
two anvil pieces 8. 7. will break the circuit of the magnet M¹ thus permitting the
signal a to pass over to the safety position as desired where it will be held by the
magnet:M, the circuit L of which is then closed and in the further movement of
the switches S. St. the other circuit L' will also be restored to its normal closed:
position.
By having the circuits of both magnets M. M¹ normally closed any failure of
either circuit will be indicated, that of the magnet M by the main signal a. taking
the danger position and that of the magnet M by the signal a' taking the danger
position.
It is obvious that the magnets M. M'. and their circuits might be employed with
a signal a. which is moved positively in one direction by the action of the proper
magnet unassisted by gravity, and the magnets are preferably of sufficient strength
to move the signal from an intermediate position up to their poles. By arranging
the signal as a pendulum as shown only a very small magnetic force is required to
operate it.
It is not necessary that the signal a'. should move with great promptness and it
may therefore be nearly counter balanced as by the weight W so that but slight
power is required to move it. For double track roads it is not necessary to
extend the circuit L of the magnet M beyond the signal post containing the said.
magnet and in this case the magnet M¹ and signal a¹. alone would be depended upon.
for indicating breaks in the track, it being controlled by a suitable switch shown
at S Figure 2.
For single track roads where trains enter a section from both ends and it is
desirable to set a signal both ahead of and behind the train, the arrangement shown
in Figure 5, may be employed.
In this case the instruments in the circuit L of the magnet M. one at each end
of the section are placed so as to be operated last by the train entering the section
and the instruments f¹ in the circuit L' of the magnets M' to be operated last by.
a train leaving the section in either direction.
A greater distance than the length of the longest train should be left between
the instruments f. f. at either end of the section or if desired a second locking
device g. may be employed to engage the signal when moving from the danger to.
the safety position. The circuit breaker for the magnet M¹ of one signal might be.
operated by the signal of the next block in advance, or, the magnet M. of each
•

page_text: :
signal might; be included in the same circuit with the magnet M' of the first or
second signal in the rear so that a single circuit breaker will operate to set the
signal at the entrance of a block entered by a train to danger, and also set a
preceding signal the protection of which is no longer needed to the safety position.
In the modification shown in Figure 18, the magnet M instead of acting directly
upon an armature attached to the signal carrying arm d. acts upon an armature c².
provided with a latch c. which engages the end of the signal arm b. and retains
the signal concealed. In this case the magnet M¹ is in a normally open circuit
and is closed by the train passing off the section to restore the signal. to its
safety position.
:
In this case the signal drops under the action of gravity into the vertical position
where it indicates danger, this movement being limited by a stop pin c*.
The signal apparatus illustrated in Figures 7 to 16, is slightly different from that
already described, the signal arm b. vibrating above and below a horizontal position,
and being connected by a link j with an armature lever k pivoted at.25. In
Figure 7, the apparatus is shown as applied to a block section of a single track
road. The main line L connects the magnets M by which the signals are controlled
and from which the circuit is continued through the battery B and circuit breakers
ffone at either end of the section to pole changing instruments k. k¹. from which
the circuit is continued through the batteries B³ to the ground.
The pole changers m. m' each consist of an armature. controlled by the trains
leaving the sections as before described the said armatures being divided by insu-
lating material into two electrically separated parts one connected with the main
line Land the other connected with the earth E in all positions of the said
armature.
The batteries B³, have one pole as the one marked 4 connected by wire 21 with
a contact point arranged to connect with one portion of the said armature when in
its normal position and the same pole is also connected by wire 22 with a contact
point arranged to connect with the other or grounded portion of the said armature
lever when depressed by the attraction of the magnet f³. when its circuit is closed
by the wheels of the train leaving the section.
The other pole of the battery is connected by wires 23. 24 with contact points
each arranged to be in contact with the other portion of the said lever than that
connected with the other pole of the battery in either position of the said armature
lever. The batteries B'. have similar poles connected with the line and with the
ground when the instruments m are in their normal position so that the said
batteries neutralize one another and have no effect upon the magnet M.
The battery B is of such strength that it will retain the armatures of the
magnets M attracted when they are near the poles of the said magnets thus
holding the signals in the safety position, but the current of the said battery will
not produce sufficient power in the said magnets to cause them to attract their
armatures when retracted in other words to remove the signals from the danger to
the safety position.
In operation when a train enters a section it first effects the instrument m. at the
end of the section thus entered thus reversing the pole connections of the adjacent
battery B2 with the line and earth thus causing the said battery to act in conjunc-
tion with that at the other end of the section, which however produces no effect
upon the signals a as their armatures k are already attracted by the magnets M.
Immediately after passing the said instrument m it returns to its normal position
setting the batteries B in opposition to one another after which the train operates
the circuit breaker f wholly opening the main line L demagnetizing the magnets
M and permitting the signal to move to the danger position.
. When the train passes the circuit breaker f the latter again closes the line L
but the current of the battery B is insufficient as before mentioned to restore the
signals to their safety, position so that they remain indicating safety while the
train traverses the section.
:
I
In passing off the section the train first perates the circuit breaker f¹ which

page_text: produces no effect upon the signals as they are already in the danger position and
in the further movement of the train the said circuit breaker f¹ is left closed and
the pole changing instrument m operated to reverse the polarity of the battery B³,
in the line thus setting both batteries B², in conjunction with one another when
their combined power is sufficient to restore the signals to their safety position
where they are, held by the current of the battery B ready to be set at danger
again upon the next operation of one of the circuit breakers for f' as before
described.
The apparatus shown in Figure 8, operates in substantially the same way as that
shown in Figure 7 just described except that the instruments m. m¹ instead of
reversing the polarity of the adjacent battery merely remove the said battery from
the circuit and connect the line L directly by wire 26 with the earth thus leaving
the battery B, at the other end of the, section to act unopposed, the said
batteries B². each of sufficient power when acting either opposed or assisted by the
battery B to restore the signal to the safety position.
In
When desired to set the signals to danger otherwise than by the automatic action
of the train as for example at a railway switch at some intermediate point in the
block section this can be done by the electric switch S. which when in the dotted
line position leaves the line L open and the signals consequently at danger.
restoring the switch S to its normal position it passes over a button or anvil S³,
connected with the earth E as shewn, the said button S. and the contacting face of
the switch S. being of such size that the switch will close the line L before it
leaves the said button S, thus affording an independent circuit for each of the
batteries B. which thus restore the respective adjacent signals to the safety position
just before the switch S closes the main line causing the battery B to retain the
said signals in the safety position.
In the modification shewn in Figure 9, the main line L containing the
magnets M and battery B by which the signals are retained in their safety position
and the circuit breakers f by which the signals are caused to drop to the danger
position is independent of the line L' containing the magnets M¹ and batteries B²,
with the pole changing instrument m m¹. by which the signals are restored from
the danger to the safety position.
In this case a double electric switch S. S'. has to be employed the two, portions
being mechanically connected for simultaneous operation and the portion S';
cooperating with an anvil piece or button S' ground both portions of the line L'
affording, independent circuits for the batteries B³, by means of which the
magnets m¹. are charged and the signals restored to their safety position.
In this construction the actuating magnets M' are placed near the pivotal points
of the armature-levers k, where the amount of movement of the said levers is small
while the retaining or locking magnets M are placed near the free end of the said
armature lever where the amount of movement in the magnetic field is so large, so
that the said magnets M have but very slight power to restore the signals to the
safety position although amply powerful to retain them there when moved by the
magnets M¹.
In the apparatus shewn in Figure 10, the signal actuating armature lever k of
one of the signals is arranged to operate a pole changing device n shown as con-
sisting of a block of insulating material n'. see Figure 11 mounted to rotate upon
an arbor n. and provided with pins n³. n. connected with the poles of a battery B
and resting in contact with springs ns. n°. forming the terminals of the line L
external to the said battery.
The said block is provided with a pinion n. actuated by a gear n³ connected
with the end of the armature lever k. so that when the said lever is retracted upon
the demagnetization of the magnet M it will rotate the said block in the direction
of the arrow until the pins n³. n. are brought into contact with the opposite ones
of the springs n. n. thus reversing the connection of the poles of the battery with
the circuit external thereto..
...The line L includes the magnets M. at the ends of and other desired points in
'
'

page_text: the circuit and at one end of the circuit is continued through the pole changer n
and battery B to the ground through the circuit breaking instrument f while at
the other end the circuit is continued through another battery B and circuit
breaker f to the ground E.
In the normal position of the signals and pole changer m. and battery B acts in
conjunction with the battery B' thus retaining the signals at safety, but when the
circuit is broken at for f¹. by a train entering the section at either end, the
signal drops to the danger position and in so doing reverses the polarity of
the battery B in the line so that the batteries B. B¹. now oppose one another and
do not operate to restore the signals to the safety position.
.
In order to restore the said signals to safety, branch wires L. are connected with
the main line L between the battery B¹ and the magnet M by the armature of
which the pole changer n is controlled. The said branch wires L. contain normally
open circuit closers m. m'. adapted to be closed by the train leaving the section
and thus permitting the battery B to act unopposed by the battery B' upon the
magnet M which actuates the pole changer m, thus restoring the signal and pole
changer to the normal position so that the battery B will act in conjunction
with the battery B₁ The signals can be set from an intermediate point in the
section by means of the switch S, which opens the line L and in closing the said
line, first grounds by the branch L³. the portion of the line containing the magnet M
which actuates the pole changer n and also containing the battery B controlled by
the said pole changer thus causing the said battery to restore the said signal pole
changer and battery to their normal condition when the line is closed As shown
in Figure 13, the magnet M at one end of the section operates a pole changer n
which may be the same as that shewn in Figures 10 and 11 or as shown in
Figures 12 and 13 consist of two bars nº n. insulated from one another and
connected respectively with the terminals of the line L the said bars being connected
by a link n with the armature lever k, of the signal and being provided at one
pair of adjacent ends with wires n¹³. n which in the normal position of the said
levers dip in mercury in cups n. 18 connected with the poles of the battery B.
The other ends of the bars n³ nº. are provided with wires n17 18 which normally
stand above the surface of mercury in the cups n¹º n. which are respectively
connected with the opposite poles of the battery to those connected with the
cups n15 16
When the signal moves to the danger position the bars 10. are rocked on their
pivot n. raising the wires n". n. from the mercury in the cups n¹5. n. and
causing the wires n. 18. to 'dip in the mercury in the cups n¹. 20. thus reversing
the connection of the poles of the battery with the bars ns. n¹º. and connected
terminals of line L.
The main line L at one end of the section passes through the magnet M pole
changer n. and battery B and the circuit breaker f to the earth E while at the
other end of the section it passes through the magnet M circuit breaker f¹. to one
terminal of the polarized relay P, the other terminal of which is connected by.
wire 28, with the armature lever o of the said relay and also by wire 29 with the
resistance coils R from which the circuit is continued to the ground E.
The armature lever o of the relay P has a contact point connected with the
wire 30 leading directly to the ground E so that when the said armature is in
contact with the said point the current of the battery B has a direct path from the
said relay through the wire 28 armature o. and wire 30 and it is not weakened by.
traversing the resistance R.
This is the normal position of the armature o of the relay R under the action
of the current which traverses the line when the pole changer n operated by the
armature lever k is in its normal position, the said armature lever k being attracted
and the signal at safety. When a train enters a section it opens the circuit
breaker for f'. demagnetizing the magnets M permitting the signals to drop to the
danger position and in the said movement change the position of the pole changer n
reverses the polarity of the battery B in the line L and relay P so that as soon as

page_text: the circuit is again closed after the train has passed the breaker for f¹, the position
of the armature lever o of the polarized relay P is changed breaking its contact
with the wire 30 so that the current is now compelled to pass through the wire 29
and resistance R and is so weakened by the said resistance as to be insufficient in
acting on the magnets M to move their armatures and restore the signals to the
safety position.
}
The signals are restored to their safety position by means of branch circuits L.
connected with the line L between the battery B with the magnet M by which the
pole changer n is operated on the one side, and the resistance R on the other side.
The said branches are provided with normally open circuit closers m. m³. located so
as to be operated after the corresponding circuit breakers f. f'. at the same end of
the section by a train leaving the section but before the said circuit breakers by a
train entering the section.
In operation the train entering the section breaks the circuit, reverses the
polarity of the battery and introduces the resistance as before described leaving
the signals at danger and in passing off the section it closes one of the branches L'
removing the resistance R and causing the battery B to act with its full power
upon the magnet M by which the pole changer n is actuated restoring the signal
to the safety position and the pole changer to its normal position so that the
current is reversed and the small portion of it which passes through the coils of
the relay P wire 29 and resistance R is sufficient to restore the armature o of the
said relay to its normal position in connection with the wire 30, thus removing the
resistance R from the circuit, or more properly speaking providing an additional
circuit without the said resistance so that the battery acts with its full force to
retain the signal in its safety position. It may be that the relay P will not be
effected by the portion of current passing through the branch 29, R while the
branch L is closed, but the moment the latter is opened the said relay will be
affected closing the branch 30 before the armature of the magnet M is moved
sufficiently to again reverse the pole changer.
The signals may be set otherwise than by the train by means of the switch S
operating similarly to the one described in connection with Figure 10, it affording
a circuit for the battery B and signal magnet M by which the pole changer is
operated so that when the line is closed by the said switch after having been
opened by it, the signal and pole changer are first restored to their normal
position thus placing the relay P and the entire apparatus in the normal condition
when the line is closed.
In the form shown in Figures 14 and 15, what are known as differential magnets
are employed, the cores of the said magnets being wound with two coils in separate
circuits and the said cores being magnetized by the sum or difference of the
currents in the said coils according as they act with similar or contrary effect:
The circuit of one of the said coils contains a pole changer which is reversed by
the movement of the signal from one to the other position, the said pole changer
keeping the two currents in unison, or with similar effects on the magnets while
the signals are at safety but setting them in opposition when the signals are at
danger.
In order to restore the signals to safety after they have been set at danger and
the currents are in opposition, one of the circuits is broken leaving the other
current to act unopposed and restore the signal to safety, and in order to set the
signals to danger when they are at safety and the currents in unison both circuits
are broken simultaneously, thus wholly demagnetizing the magnet. In Figure 14;
the apparatus is shown as arranged for a single track road. The signal actuating
electro magnet M has two independent coils r. 7. and the armature lever k thereof
is connected by the link n¹. with the pole changing device n. which may be the
same as that described in connection with Figures 10 and 12.
The battery B is connected with the said pole changing device and the line L
including one coil . of the magnets M and also including circuit breaking instru-
ments m. m. adapted to be operated when the train is leaving the section at either

page_text: end and also including circuit breaking instruments f. f¹. adapted to be operated
after the adjacent instrument m. m². by a train entering a section at either end.
The said instruments ff. also operate as circuit breakers for the line L'.
including the coils r. of the magnets M and also including the battery B. In the
normal condition of the signal when indicating safety the connection of the pole
changer n. is such that the current of the battery B produces in the coil r. of the
magnet M a similar magnetic effect to the current of the battery BS in the coil r'.
so that the said magnet is magnetized and the armature k held or attracted by the
combined power of both batteries. When a train enters a section it first operates
upon the circuit controlling instrument m, or m¹. opening the circuit of the
battery B which produces no effect on the signal as it will still be held at safety by
the current of the battery B2, in the coil r¹, of the magnet, but when in the further
movement of the train it arrives at the instrument for f1, both circuits Land L'
are broken simultaneously thus completely demagnetizing the magnets M and
permitting the lever k. to be retracted, the signal to be moved to the danger
position and the pole changer n to reverse the polarity of the current of the
battery B acting on the coil 7 of the magnet M.
When the circuits are again closed the current of the battery B having its
polarity thus reversed will act on the coil r. of the magnet M with the opposite
effect to the current of the battery. B*, on the coil . of the magnet M which is
thus magnetized only by the difference in effect of the said currents which is not
sufficient to attract the armature and move the signal to the safety position. When
the train passes off the section the circuit L of the battery B is opened by the
instrument m or m³, while the circuit L of the other battery B³, is closed so that
its current acts upon the coil r¹ of the magnet unopposed by the current of the
battery B and the said battery is made of sufficient power to attract the
armature k. and set the signal to safety when thus acting alone unopposed. In
the return movement of the signal to the safety position the pole changer n. is
restored to its normal position so that when the circuit L is subsequently closed
the two currents will act in conjunction as before to retain the signals in the safety
position until both circuits are again broken at once by the instrument for f'.
When desired to set the signals to danger and safety by an instrument other
than the breakers f. f¹. m. m³. operated by the trains it can be done by means of
the switches S, S'. mechanically connected together, so that they open both
simultaneously when moved from the full to the dotted line position thus setting
the signals to danger.
'
To restore the signal to the safety position it is necessary that one circuit should
be closed before the other so that the pole changer n may be restored to its normal
position by the action of one unopposed current before the other current is
applied. This is accomplished by extending the contacting face or anvil piece of
one of the switch arms as shewn at 9 so that in the return movement from the
dotted to the full line position the current L. controlled by the switch S' will be
closed before the other circuit.
The apparatus is shown in Figure 15 as applied to a double track road. In this
case the circuit of the battery B and coil r of the magnet M is merely localized
through the said battery, coil, and the breaker f, while the circuit of the battery B
including the pole changer n. is extended throughout the section and provided
with the circuit breaker m. at the other end of the section operated by trains
passing off to break the said circuit and permit the battery,B. to act unopposed
and thus restore the signal and pole changer to their normal or safety position.
Signals can be operated by a magnet in the circuit of the battery B alone, they
being of such nature that the reversal of the current causes a change of position of
the armature and signal actuated or governed thereby.
Such a signal is shown as controlled by the magnet M³ having a permanently
magnetized core, the permanent magnetization of which corresponds with the effect
of the battery B2, and coil on cores of the magnets M so that when the current
of the battery B is of its normal polarity, it acts to increase the magnetism of the

page_text: :
core of the magnet M³ thus causing it to attract and retain its armature up to
its poles.
3
When however the said current is reversed by the action of the pole changer n
the effect of the current is to neutralize the permanent magnetisin thus causing
the magnet M³ to cease to attract its armature which in Figure 14 is shown as a
pointer indicating the safety or danger condition of the circuit according; as it is
opposite the letter S or D.
T
It will be understood that the magnet M having coils included in both circuits
could be employed to control the movement of the pole changer and that
independent magnets could be employed to actuate all the signals, the said magnets
being operated by the change of condition of the circuit of the magnet M.
In form shewn in Figure 16, the signals are set to danger by breaking the
circuit and are retained in the danger position by the interposition of resistance in
the circuit which so weakens the current that it cannot restore the signals to
safety, the operation thus far being similar to that of the apparatus shown in
Figure 13.
The introduction and removal of resistance by which the signal is retained at
danger or permitted to remain at safety is accomplished by an electric switch in
the circuit which is itself controlled by the change in resistance produced by it..
Resistance is employed located partly at each end of the section and of such
amount that when the resistance at both ends is introduced at the same time it
renders all the magnets in circuit unable to move their armatures. but when that
at one end only is in circuit it leaves the resistance-controlling switch actuating
magnet sufficiently powerful to move its armature.
Branch circuits are employed interposed between the resistance on the one side
and the switch controlling magnet on the other side so that when the said branches
are closed, one portion of the said resistance is removed from the circuit, leaving the
switch operating magnet sufficiently powerful to attract its armature and thus
remove the resistance controlled by it.
:
The main circuit L which is normally closed may be traced as follows;
beginning at the earth. E at one end of the section it passes by wire 30 to the
resistance R from which it is continued by wire 31 to one electrode of the switch
magnet t. the other electrode 32 of. which is connected with the line L including
the circuit breakers f. f. and the signal actuating magnets M and battery. B and
connected with the switch magnet t'. at the other end of the section from which
the circuit is continued by wire 35 to the resistance R' and thence completed by
wire 36 to the ground E.
The armature levers u. u. of the switch magnets t. t. are connected with the
wires 31 and 35 respectively between the adjacent resistance and the coils of the
said magnets and the said actuating levers are provided with contact points y. y¹.
with which they make connection when attracted.
The said contact points y. y. are connected by wires 37. and 38 respectively
with the wires 30 and 36 between the resistance R. R' and the ground so that
when the armatures u. u. are attracted this being the normal condition, a circuiţ
is afforded from E to El by wires 30. 37, point y, armature lever u, magnet t line L.
including the magnets M and battery B, magnet t'. armature lever u¹. contact point y¹
and wires 38 and 36 in which the current is not compelled to traverse and bo
weakened by the resistance R and R'; and the current of the battery B is of
sufficient strength when acting without the resistance to attract.-and retain
attracted the armatures of all the various magnets included in the said circuit.
.
When however the circuit is broken as by the action of a circuit breaker for f¹
by a train entering a section from either end, the inagnets are all demagnetized
thus permitting the signals to drop to the danger position and the armatures u. u¹..
to be removed from contact with the points y. y. so that when the circuit breaker
again closes after the train has passed the only circuit afforded between the wires
30, 31 and 35, 36, includes the resistance R. R' respectively, thus weakening the

page_text: current so that none of the armatures are attracted and the signals will
consequently remain in their danger position.
When it is desired to restore the signals to their safety position it is necessary
to move the whole or one portion of the resistance R. R¹ from the circuit.
This is accomplished by means of branch circuits 39. 40 connected with
wires 31 and 35 respectively and the ground, the said branch wires containing
normally open circuit closing instruments m. m. arranged to be operated by a
train after they have passed the adjacent circuits f. f. in leaving the section.
When either one of the said circuit closers operated by the train leaving the
<section at either end a circuit is afforded through the branch wires 39 or 40, to the
wire 31 magnet t, and thence to the other end of the section as before described so
that the circuit is not compelled to traverse and be weakened by that portion of
the resistance adjacent to the circuit closer mor m² and branch thus operated
and the switch magnets t. t. are so adjusted that their armatures will be attracted
when one portion of the said resistance is removed from their circuit, thus
connecting the armatures u. u. with the points y. y'. and affording a direct circuit
therethrough between the wires 31. 37, and 30, and 35, 38 and 36 as before described
Bo that the battery acts with full effect upon the signal actuating magnet M..
It will be understood that the signal actuating magnets may also be properly
constructed or adjusted to move their armatures when the circuit passes through
only one portion of the resistance but not when it passes through other portions
in which case one of the switches with its operating magnet might be omitted,
the line L for instance being connected directly with the wire 31 and the wire 37
with the parts t. u. y. being omitted but it is preferable to employ both switcheś
so that the signal actuating magnets M will be effected by the full power of the
circuit.
When desired to operate the signals otherwise than by the instruments f. fl. m.
m². automatically operated by the train, this can be done by any circuit controlling
switch as the one S the said switch in its return movement by which the circuit
is closed connecting the portion of the line L, that includes that battery B with the
ground, and thus removing that portion of the resistance which is located at the
other end of the said line.
The anvil piece S³, of the said switch is connected by the wire 42 with the
ground E and in moving it from the dotted to the full line position for the
purpose of closing the main line L a circuit is afforded for the switch actuating
nagnet including only the resistance R at the same end of the section so that
ite armature will be moved up thus cutting the said resistance out of the circuit
and consequently causing the armature of the other switch magnet M to be moved
up as soon as the switch closes the main line which it does before being actually
disconnected from the anvil piece S. and the ground. The resistance is spoken of
as being cut out or removed from the circuit when an additional direct circuit is
afforded as the resistance then has no tendency to weaken the circuit as is the
case when no such additional direct circuit is afforded.
Figure 17 illustrates the arrangement of the signal for a single track road by
which the possibility of two trains approaching one another in opposite directions
without each giving the proper danger signal to stop the other without collision is
prevented. The signals at the opposite ends of the section are connected together
for simultaneous operation by a train entering at either end of the sections as
illustrated in Figures 5. 7, 8. 9. 10 13. 14 and 16, and it will be seen that if two
trains should enter the section simultaneously at the opposite end each would
operate to set the signal and each engineer would suppose that it was only his own
train that was operated by the signal and would not be made aware of the
approach of the other train. The block sections are however so overlapped that
two trains cannot arrive simultaneously at opposite ends of the same section
without having previously set other signals within the said section which will serve
as a warning to the trains before they meet one another within the said section.
The pairs of signals in the said circuit are arranged on opposite sides of the track

page_text: Bo that the signal passed in entering a section will always be on the same side relative
to the engineer and the signal passed on leaving the section will be on the opposite
side relative to the engineer regardless of the way in which he is travelling.
For instance if the signal that he sets on passing into the section is on his right
hand and the signal that is simultaneously set at the end of the section in advance on
his left hand, and each engineer will consequently pay no attention to the signals on
his left hand as they are set by his own train, but he will be stopped by the
signals on his right hand as he will know that they were either set by another
train in advance of his own and travelling in the same direction or by a train
approaching him from the opposite direction.
In passing along the track in either direction the signal at the advanced or
remote end of each section is beyond the signal at the nearer end of the second
section in advance by more than double the resistance required to stop any train.
In Figure 17 the two signals in the same circuit connected by the dotted lines
and have the same letters of reference one of them being distinguished by the
mark () as T. T¹. U. U¹.
It will be seen that looking in either direction as from left to right the remote
signal as T of one section is beyond the nearer signal of the second in advance
namely the one marked V by a distance at least double what is necessary to stop
a train.
This arrangement is continued through out, the signal U¹ being such a distance
beyond the one W and so on.
A train moving from left to right as indicated by the arrow 7, on arriving at or
near the signal T, sets both the signals T. T. to danger and it will be seen that a
train moving in the opposite direction as represented by the arrow 2, cannot arrive
at the signal T¹ which is thus set to danger without first passing both the signals V'
and U¹ and thus setting the signals V and U which would serve as a warning to
the train which had passed the signal a.
If the train 2 arrives at the signal U1 before the train 1 has arrived at the
signal U, the said train N° 1 will be warned by the said signal U and will stop
while train N° 2 continuing beyond the signal will be warned by the signal T¹.
If however both trains should arrive at the signals U, U. so nearly simultaneous
that each engineer might suppose that the signal was set by his own train, both
trains would continue on their way when the engineer of train number 1 would
perceive the signal V set at danger and would immediately stop, while the engineer
of train No 2 would find a danger signal at T' and would also stop, there being
sufficient space as before mentioned between the said signals V and T¹, to permit
both trains to be brought to rest before actually meeting.
The signal T' cannot be restored to safety until train N° 1 passes it and the
signal V cannot be restored to safety until train N° 2 passes it and it will be seen
that neither train can restore the corresponding signal to safety without passing
the danger signal set by the other train which it is not permitted to do The
term section is used to designate the space along the track included between a
connected pair of signals as between the signals T. T¹. U. U¹. etc.
It does not refer to the rails of the track themselves but merely to space or
distance so that the said sections may be properly described as overlying extending
into, or overlapping one another.
Having now described and particularly set forth the nature of the said invention
and the manner of carrying the same into effect I would have it understood that
what I claim is :-
1 In railway signal apparatus the combination of the following elements; the
main signal, an electro magnet and circuit controlling instrument operated by trains
entering the block section guarded by the said signal, an electro-magnet and circuit
controlling instrument operated by the train leaving the said section and a
econdary signal, the said main signal being controlled in its movements by each of
he said magnets in turn and the secondary signal being controlled only by the
ast mentioned magnet, substantially as described.

page_text: 2nd The combination with the main signal of an electro magnet and its circuit
and normally closed circuit breaker operated by the train entering the section,
and an electro-magnet, its circuit, and normally closed circuit breaker and means
to open it when the train leaves the section, the movements of the said signal being
controlled by each of the said magnets in turn, when the normal condition of the
said circuit breakers is changed upon the passage of a train substantially as
described.
3rd The main signal electro magnet, and normally closed circuit breaker opened
by a passing train combined with a second electro inagnet which controls the said
main signal after the said circuit breaker is operated, and a circuit controlling
instrument in the circuit of the said second magnet, the condition of which is
reversed while the train is passing it, and a secondary signal controlled wholly by
the said magnet and thus indicating the condition of the circuit controlling
instrument substantially as described.
4th The signal combined with two electro magnets in normally closed electric circuits
respectively provided with circuit breaking instruments at the entrance and end of
the block section, the said signal being moveable from control of one, into control
of the other of the said magnets upon the opening of the instrument in circuit of
the magnet at that moment controlling the signal substantially as described.
5th The signal and two electro magnets, combined with means to primarily
retract the signal from one of the said magnets towards the other, and a locking
device by which the said signal is retained, thus positively retracted until engaged
and wholly retracted by the said magnet towards which it is moved substantially
as described.
6th The signal and two electro magnets controlling its movement from one to the
other position, the circuit of each of the said magnets being normally closed when
the signal is moving into and retained in control thereof combined with a self
closing circuit breaker in circuit with one of the said magnets adapted to be held
open by the signal while under the control of the other magnets substantially as
described.
7th The signal and electro magnet by the attraction of which it is held in the
safety position, combined with a circuit breaker in circuit with the said magnet
adapted to be held open by the signal while in its danger position, and an
indicating electro magnet and signal in the said circuit whereby the condition of
the main signal is indicated, substantially as described.
8th The signal and its two controlling electro magnets and circuit breaking
instruments in their respective circuits the said instruments remaining closed
except when positively held otherwise, combined with independent indicating
electro magnets and signals in each of the said circuits, substantially as described.
9th The signal and its two controlling electro magnets and normally closed
circuit breakers in their respective circuits combined with an electric switch in
circuit with both the said magnets substantially as described.
10th The signal its two controlling electro magnets and locking device operating
as described, combined with an electric switching apparatus in circuit with both
the said magnets and adapted in its movements to its normal position to first close
both circuits, then open one of the said circuits and finally again close it leaving
both circuits complete at the said switch, substantially as described.
11th The signal arm provided with a projection and signal hung thereon to
swing as a pendulum under the action of gravity, combined with the pivotal
locking device having its engaging portion in the path of the said projection
whereby when the said signal makes less than a complete oscillation, the said
projection is engaged and prevented from return movement by the said locking
device but when it makes a complete oscillation it passes out of engagement with
the said locking device and is permitted to make a return movement, substantially
as described.
12th The signal and the electro magnet by which it is controlled, combined with
two independent batteries both normally in circuit with the said magnets but

page_text: acting in opposition to one another, and a circuit controlling instrument for one of
the said batteries automatically operated by the passing train whereby the said
battery may be removed from the circuit of the said magnet or have its polarity
reversed therein leaving the other battery to act unopposed or assisted upon the
said signal controlling electro magnet, substantially as described.
13th In a railway signal apparatus, the combination of the signals, their
actuating magnets and circuit therethrough with independent actuating batteries
normally in circuit with the said magnets and opposed to one another and
corresponding independent circuit changing instruments at each end of the block
section automatically actuated by the train by means of which the battery at either
end of the section may be made to act unopposed by that at the other end
substantially as described.
14th The signal and electro magnet and its armature to operate it with a
normally closed circuit through the said magnet and generator therein of sufficient
power to cause the magnet to hold the said armature when attracted, but
insufficient to move it when retracted and an actuating battery normally inactive
in the said circuit and a circuit controlling instrument therefore operated by the
train in passing by which the said battery may be caused to act in the said circuit,
substantially as described.
15th The signal and electro magnet and armature by which it is actuated
combined with two batteries normally set in opposition in the circuit of the said
magnet and an electric switch by means of which the conductor joining one pair
of like poles of the said batteries may be connected with the conductor or ground
joining the other pair of like poles, and an independent circuit thus formed for
each battery in which it acts unopposed substantially as described.
16th The signal actuating electro magnet, an armature and circuit through the
said magnet, connected with one portion of a circuit controlling instrument the
other portion of which is connected with the ground or other terminal of the
circuit combined with a battery having its two poles respectively connected with
the two portions of the said instrument when in its normal position the said poles
also being connected with contact points by which the said poles are connected in
the inverse order with the same portions of the said instrument when moved from
its normal position substantially as described.
17th A signal operating electro, magnet and divided battery and circuit breaker
in circuit therewith, combined with a pole changing device operated by the said
signal in its movement which takes place when the circuit is broken whereby the
position of one portion of the said battery in the said circuit is reversed and it
operates to neutralize the current of the other portion, substantially as described.
18th The signal operating electro magnet divided battery in circuit therewith and
pole changing device for one portion of the said battery operated by the signal
combined with a circuit between the two portions of the said battery and a circuit
controlling device therein whereby one portion of the battery is caused to act
independently and its polarity is changed in the consequent movement of the
signal, substantially as described.
19th The signal operating electro magnet and divided battery and normally
closed circuit breaker in circuit therewith, combined with a pole reversing device
for one portion of the said battery operated by the said signal in its movements
caused by the said magnet and a normally open branch circuit and circuit closer
therein between two portions of the battery, substantially as described.
20th The signal actuating electro magnet and divided actuating battery in circuit
therewith, combined with a pole reversing device for one portion of the said battery
operated by the said signal whereby when the signal is in one position the two
portions of the battery are opposed to one another and when in the other position
they act in conjunction substantially as described.
21 The signal operating electro-magnet, divided battery in circuit therewith
and pole changing device for one portion of the said battery operated by the said
signal in its movements, combined with an electric switch in the said circuit and a

page_text: branch circuit for the said portion of the battery having an anvil or contact piece
engaged by the said switch in its movements by which the main circuit is closed,
substantially as described.
22nd In a railway signal apparatus, the signal actuating magnet in a normally
closed circuit, combined with a circuit breaker and relay or circuit changing
magnet in the said circuit and resistance interposed and retained therein by the
said relay when the said circuit is broken and subsequently closed, substantially as
described.
23rd The signal operating electro magnet, and relay, combined with branch
circuits from the said signal operating magnet of different resistance controlled by
the armature of the said relay, substantially as described.
24th The signal actuating magnet, the relay and the resistance interposed in the
circuit of the said magnet by the said relay combined with an independent circuit
and closer including the said signal actuating magnet and battery without the said
resistance substantially as described.
25th The electro magnet and pole changer controlled by it, combined with the
polarized relay and resistance controlled by it in accordance with the condition of
the said pole changer and its controlling magnet, substantially as described.
26th The electro magnet and pole changer controlled thereby and the polarized
relay controlled by the said pole changer, combined with resistance interposed by
the said relay when the pole changer is reversed by the demagnetization of its
controlling magnet, and an independent branch circuit and circuit closer between
the said magnet with its battery, and the resistance whereby the magnet is caused
to attract its armature and thus cause the pole changer and polarized relay to be
restored to their normal condition and the resistance removed from the circuit
substantially as described.
27th In a railway signal apparatus the electro magnet having two coils in
independent circuits, combined with the pole changing device in one of the said
circuits operated by the armature of the said magnet substantially as described.
28th The combination of the electro magnet having two coils in independent
circuits, the circuit breaker by which both said circuits are broken at the same
time and the electro magnet demagnetized, and the pole changer in one of the said
circuits operated by the armature of the said magnet whereby after the movement
of the said armature froin the poles of its magnet, the current in the said circuit is
made to act in opposition to the current in the other circuit on the cores of the
said magnet substantially as described.
29th The combination of the electro magnet having coils in two independent
circuits, the pole changing device in one of the said circuits operated by the
armature of the said magnet whereby in the movement of the armature from the
poles of its magnet, the current controlled by it is set in opposition to that in the
other coil of the said magnet, and a circuit breaker in one of the said circuits only,
operated by trains passing off from the section whereby the magnet is acted upon
by the unopposed current in the unbroken circuit, its armature attracted thereby,
and the pole changing device restored to the position in which both currents act in
conjunction when the circuits are both closed substantially as described.
30th The electro magnet having two coils in independent circuits combined with
a pole changing device operated by the armature thereof in one of the said circuits
and an electric switch having mechanically connected arms one for controlling each
circuit, and provided with an extended contact for one of the said arms whereby
in closing the said switch, one of the said circuits is closed before the other,
substantially as described.
31 The combination of the electro magnet having two coils in independent
circuits, the pole changing device for one of the said circuits operated by the
armature of the said magnet, the circuitbreaker operated by trains entering the
block section by which both circuits are opened at the same time, and the circuit
breaker operated by trains leaving the section by which one circuit only is opened
substantially as described..

page_text: 32nd The combination with the signal actuating electro magnets of a switch
operating electro magnet and resistance interposed in the circuit of the said switch
operating magnet by the movement of its armature when retracted upon the
opening of the circuit, whereby the said armature is retained retracted after the
subsequent closure of the said circuit substantially as described.
33rd In a main signal controlling electric circuit and switch operating electro
magnet therein combined with resistance in two portions, one located near each end
of the said section, one of the said portions being interposed in the said circuit by
the armature of the said magnet when retracted, and a branch circuit between one
portion of the said resistance on the one side and the battery with the said magnet
on the other side whereby the said battery is caused to act upon the said magnet
unaffected by the said resistance when the said branch circuit is closed substantially
as described.
34th The main signal controlling electric circuit and two switch operating electro
magnets therein combined with resistance one portion of which is introduced into
the circuit by the armature of each of the said magnets when retracted, the said
resistance and magnets being adjusted as described whereby when the entire
resistance is in circuit the said armature remains retracted but when either portion
of the said resistance is removed the said armatures are retracted and thus remove
the entire resistance substantially as described.
35th The combination of the signal actuating magnets, the switch magnets, and
resistance interposed in circuit thereby, the circuit breakers, and branch circuits
and circuit closers therein whereby the said resistance is removed from the circuit
of the said switch magnets and is retained thus removed by their consequent
operation, substantially as described.
In witness whereof I the said William Morgan Brown have hereunto set my
hand and seal this Sixth day of March in the year of our Lord One thousand
eight hundred and eighty three.
W MORGAN BROWN (LS.)