Improvements in Electrical Apparatus for Use in Controlling Semaphore and other Signals.
Year: 1893

page_text: Date of Application, 24th Oct., 1893-Accepted, 10th Mar., 1894
COMPLETE SPECIFICATION.
Improvements in Electrical Apparatus for Use in Controlling
Semaphore and other Signals.
We MICHAEL BARRY LEONARD of Chesapeake and Ohio Railroad Richmond
Virginia U.S.A., Electrician and ELECTRIC SELECTOR & SIGNAL Co. of West
Virginia U.S.A. a company duly organized according to the laws of the State of
West Virginia 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 :-
Our invention relates to improvements in electric apparatus for use in controlling
semaphore or other signals, such as are usually employed in lock and block
signalling between, two stations or block offices upon steam railroads; and one
object of the invention is to provide means which will require the concerted action
of the operators at each of the two stations to permit a train to enter the block;
the operation of the apparatus being such that but one train will be permitted to
enter the block at a time, thereby lessening the liability to accidents.
We accomplish these results by providing each of the semaphores with a locking
device whereby the same is locked and held in position until the operator at a
distant station unlocks the same by the transmission of suitable electrical impulses
and allows the signal to be changed, and by so arranging the mechanisms that the
distant operator cannot actuate them until his own signal is in proper position to
enable him to transmit the impulses.
We also propose to use this combination for displaying stop or train order signals
at a station or stations at a distance from a central or dispatcher's office, by using a
preparing or selecting instrument adapted to respond to a predetermined arrange-
ment of electrical impulses and connecting the same with the releasing devices of
the semaphore at the distant station, and providing mechanisms to reverse the
semaphore when so released.
The usual telegraph apparatus, key, relay and sounder may be employed for
transmitting messages between the stations and on the same line may be placed
the selecting instrument to be used when the locking devices of the semaphore
require to be released and either or both may be operated without conflicting
with each other.
In this way we avoid the necessity of providing an extra wire for unlocking the
signals, and can perform the work on the regular block wire already in use.
When it is desired to operate the regular block wire independently, as for
instance in working a system of "permissive" signals, we can on one extra wire
unlock from either end of the block the semaphore or signal lever at the
other end.
This I accomplish by utilizing the principles of any of the well known duplex
telegraph systems-the Polar-Differential or Bridge-using at one office a neutral
relay and at the other a polarized relay and a rheostat placed between the main
line and such relay, and placing the unlocking magnets on one side of the local
circuits of the relay; the latter being operated from the distant stations ly
substantially the same sort of plunger at each station, causing a current of positive
or negative polarity to pass over the line and affect but one of the relays; the
relay at the station where the plunger is worked being unaffected.
may be accomplished by using polarized relays and currents of different polarity
without interposing rheostats.
The same
In the former method I use the ordinary telegraph instruments and any of the

page_text: well known forms of selecting apparatus, responding to a predetermined arrange-
ment of impulses to release the locking devices of the semaphore, and permit
the same to be reversed. And we thereby dispense with the duplex appliances,
and simply place the selector on the block wire.
The invention will first be described in connection with the accompanying
drawings, and then pointed out in the claims at the end of this description.
Inasmuch as the several electrical instruments or appliances employed in
connection with the locking mechanism which I preferably use in practicing my
invention are all old and well known in the art, separately considered, and as we
do not propose to make any specific claim herein to the construction of the
individual instruments, or appliances, we have not deemed it necessary to illustrate
or describe in detail such instruments or apparatus as may be comprised in the
complete system or combination embodying my invention; the locking mechanism
being adapted to be used in connection with a variety of instruments or appliances
which may fulfil the requirements of the combination without rendering it
necessary to use any special form or type of instrument in accomplishing the
desired results.
Referring to the accompanying drawings which form a part of this Specification;
and in which similar letters of reference are used to denote corresponding parts
of the apparatus,
Figure 1 is a diagrammatical representation of a locking apparatus embodving
my invention, adapted for lock and block signalling on the regular block wires
connecting two block offices or stations.
Figure 1 is a detail of the plunger transmitter.
Figure 1 is a detail of the locking disk.
Figure 2 is a diagrammatical view partly in section of a modification of the
apparatus adapted for displaying a "stop" or train order signal at a distant station
from the dispatcher's office.
Figure 3 is a detail plan of the unlocking magnet and locking disk shown in
Figure 2.
Figure 4 is a diagrammatical view of a further modification showing a side
clevation of the locking devices and semaphore at "station B," and a plan of the
corresponding parts at "station A."
In practice we preferably employ at block stations A and B, (Figure 1) the usual
telegraph key K, relay R, and sounder S, used for working the regular block wire,
by which the operators may communicate with each other; these devices being
arranged in the usual way, with the usual local battery circuit, so that any
particular description or illustration of the same herein is not deemed necessary.
In Figures 1 and 4 the semaphore lever A, is shown as being locked in position
with the semaphore arm (shown in Figure 1) normally at "danger," while in
Figure 2, it is locked in the same position with the semaphore arm or blade
normally at "clear."
B denotes a disk or wheel connecting with the lever A, by a link a, and having
a notch in its periphery which is engaged by one end of the armature C, of the
electro-magnet D. The armature C, may be actuated by either gravity or a
spring b, for the purpose of throwing it into engagement with the notched disk B,
when released by the magnet thereby preventing backward motion of the
semaphore lever and thus locking the block signal until the disk is released by the
operator of the distant station as hereinafter described.
It will be understood, of course, that the unlocking magnet and plunger circuit
connections with the semaphore arm or signal are the same at "station A" as
described with reference to "station B."
S¹, (Figure 1) denotes a combination lock or selector of the usual or any preferred
form, which is connected in the relay's local circuit, and D denotes the electro-
magnet which unlocks the disk and enables the signal to be operated, and is placed
in a normally open local circuit with local battery L. B.
The disk B is pierced by a hole through which passes a reciprocating bar or

page_text: plunger B', which is adapted to operate the distant semaphore or signal only when
the signal at the station whose plunger is worked in showing "danger." The main
or block wire circuit is normally closed through the plunger contacts by means of
a brush 6, connected to line and resting on the plunger bar, as shown clearly in
Figure 14, so that when the bar is moved the circuit will be opened at each
insulating space, and the circuit is thus made and broken in regular sequence, thus
producing and putting to line the desired combination or series of electrical
impulses corresponding with the particular semaphore or other signal to which the
selector at the distant station is adapted to respond, so as to close the open circuit
in which the unlocking magnet is placed, thereby energizing said magnet and
unlocking the desired semaphore, signal lever, or apparatus, and permitting the
semaphore or signal to be shown at clear."
The selector S', will respond only to the particular combination-as may be
determined-on the transmitter at the distant station. The transmitter may be of
the well known circular form indicated at T, in Figure 2, or the plunger itself may
he used for a transmitter by making it a metal bar cut with insulating spaces,
as may be desired, and as illustrated in Figure 1. If desired, however, a
transmitter may be used similar to the American District Call Box, wound up by
a lever, and the lever may be held stationary by mechanical means whenever the
signal lever is cleared at that station; the lever to be free to move only when the
semaphore or signal lever is showing "blocked" at that station.
G denotes a local battery circuit in which may be placed an annunciator
device or electric bell and visual signal G', for the purpose of indicating when the
semaphore lever is unlocked. These latter circuits are normally open and are
adapted to be closed (by the attraction of the armature C, of the unlocking
magnet D) through the contact points y, g'.
The annunciator magnet G¹, is adapted to actuate a visual signal or plate which
may drop down so as to indicate when the semaphore lever is unlocked.
The operation of this apparatus is as follows:-
Normally the signals at each local station are exhibited at "danger." In this
position the disk B is locked by the armature lever C engaging with the notch of
the disk, and the transmitter or plunger is in position to transmit the desired
combination or series of electrical impulses for unlocking the disk at the distant
station.
"
Upon the approach of a train the operator at "station A," desiring to display
his signal at clear can by the regular block wire used for communicating
between stations and the ordinary telegraph instruments transmit a message to the
operator at "station B," and the operator at the latter station, upon being requested
so to do, "plunges" or presses in the bar B', thereby effecting the necessary
electrical impulses in the main circuit and thus closing the open circuit of the
unlocking magnet at station A, and thereby unlocking the disk B, so as to permit
the semaphore or signal to be shown at "clear." When an independent circuit is
employed for the signal devices a simple closing of such circuit will energize the
unlocking magnet. When the operator at "station B" desires to allow a train to
enter his block, the operation is exactly similar to that just described with respect
to "station A." In either case it is impossible for the operator to unlock the
semaphore at the distant station until his own signal is returned to "danger." When
the armature C is attracted so as to release the wheel B, this movement of the
armature closes the contacts g, g', of the annunciator circuit, and thus actuates the
annunciator device so as to indicate that the semaphore lever has been unlocked.
With this apparatus the "answer back" and vibrating bell connections usually
employed in block signalling systems are unnecessary.
In using the combination for displaying a "stop" signal at a distant station from
the despatcher's office, as illustrated in Figures 2 and 3 of the drawings, I use a
spring or weight W, connected with the disk B, for pulling back the semaphore or
signal lever upon being released or unlocked by the magnet D; and I place the
selector S, with the desired combination, on the regular train order wire-either.

page_text: direct or through the local points of the regular relay-which wire usually passes
through every telegraph office on the railroad or any division of it; the local points
of the selector controlling the unlocking magnet being open until the predetermined
combination of signals is made on the train order wire, by means of the ordinary
telegraph key or a suitable transmitter T, at the central station or dispatcher's
office; the selector at each station being adapted to respond only to the particular
combination corresponding therewith on the transmitter at the dispatcher's office.
The transmitter may be of the circular form shown or of any preferred construction.
The signal lever will be free to move only when the semaphore or signal lever is
showing "blocked" at that station.
"
ΟΙ
6
S³, denotes a hand switch which is adapted to be moved by the operator for the
purpose of closing the unlocking magnet circuit when the local operator desires to
display a "train order" signal independently of the dispatcher's office.
The action of the apparatus in displaying "stop"
train order" signals is
simply the reverse of what it is in the lock and block signalling apparatus; the
signal being normally at "safety or "clear" and falling back to "danger" when
released from the dispatcher's office, and adapted to remain at "danger" until it is
replaced at "clear" by the operator at the local station.
"
The selector, on receiving the predetermined combination of signals from the
dispatcher's office, closes the unlocking magnet circuit, which has hitherto been
open, thereby energizing the magnet and releasing the signal lever, which is then
brought forward by the weight W, or a spring, so as to display the signal and stop
all trains until the lever is moved backward by the operator, whereupon it will be
again automatically locked, to be released only in the same way.
In operating the "stop" signal from the dispatcher's office we prefer to use an
answer back" of the well known type in common use, to notify the dispatcher
when the signal has fallen to "danger.”
It may be found useful to place these "stop" signals at points other than the
regular stations along the road, to be replaced at "clear" by say the conductor or
brakeman of a train stopped by them.
If found desirable we may use a small electro-motor to be set in operation by
the local circuit or points on the unlocking magnet, to pull back the signal lever
when unlocked by the magnet.
Referring particularly to Figure 4, P. C., at "station A," denotes a pole-changer
which may be placed in the circuit of the main battery M. B., connected to the main
line wire in the usual manner.
R' denotes a neutral relay which may be placed between the main battery and
the pole changer, for the purpose of controlling the unlocking magnet D, at that
station.
The unlocking magnets at each station are included in normally open local
circuits including local batteries L. B.; such circuits being adapted to be closed by
the action of the respective relays R¹, R², for the purpose of energizing the
magnets.
R³ denotes a rheostat placed between the main line and the polarized relay R², at
"station B" with the plunger circuit closer B' connected around the rheostat by
the wires m, m³, shunting the circuit through the plunger contacts c, c, when these
two points are closed by the plunger B'.
The contact points c, c, at each station, for energizing the apparatus at the distant
station, are arranged on one side of the disk or wheel B, which latter is pierced by
a hole through which the plunger bar B¹, passes; this hole being so located that
only when the semaphore lever is brought to "danger" will the plunger pass
through and make the contact.
G denotes the local battery circuit of the annunciator device and G¹ the
annunciator magnet and visual signal used for the purpose of notifying the local
operator when the semaphore lever is unlocked; these latter circuits at each
station being normally open and adapted to be closed by the attraction of the
armature C, of the unlocking magnets, through the contact points 9, g¹.

page_text: This arrangement is designed principally to enable the block operators to unlock
the semaphores of my system disconnected from the ordinary block wire, when it is
desired to use the block wire for actuating a "permissive" system for other purposes,
and by the use of only a single extra wire. This duplex arrangement is worked as
follows:-
Artificial resistance equal to three or four times the line resistance having been
unplugged in the rheostat R³, and the neutral relay R', having been adjusted so
that it will not respond to the weakened currents flowing through it, the unlocking
magnets can be operated from either end without actuating the magnet at the end
where the plunger is worked; this duplex action being accomplished as already
stated by utilizing the principles of any of the well known duplex telegraph systems.
The proper adjustments having been made, the circuit between the two block
stations A and B, is ready for duplex working, which is maintained as follows:-
Supposing the operator at "station A," desires to allow a train to enter, he can,
by the regular block wire, transmit a signal requesting the operator at "station B,"
to unlock his semaphore, and the operator at the latter station thereupon "plunges"
or presses in the bar B¹, thus closing the contacts c, c, and thereby affecting the
relay at "station A," which is adapted to respond every time the contact points
are closed by the plunger at "station B," the current being shunted around the
rheostat R', through the plunger contacts which practically shortens the line wire,
increasing the current flowing through the neutral relay R', and causing it to
operate and close the unlocking maguet circuit, bringing the local battery into
action and thereby energizing the magnet, which attracts the armature C, and
releases the wheel B. The same movement of the armature also closes the
contacts g, g', of the annunciator circuit, thereby actuating the annunciator device
and indicating that the semaphore lever has been unlocked. When the operator
at "station A" works his plunger, the neutral relay R', will not be affected, but
the polarized relay R³, will be actuated in the usual way, it being adapted to
respond to currents flowing from one particular side of the battery while the
neutral relay is only actuated by an increase in the quantity of the current passing
over the line.
We do not desire to confine ourselves to the described form of armature locking,
as the same result can be accomplished in a number of ways, by using other means,
adapted, like the construction shown, to relieve the strain on the armature, but I
preferably use this particular form of locking mechanism as it is simple in
construction, and reliable and efficient in use.
A bell or alarm may or may not be used in connection with the visual signal, for
directing the attention of the operator to the fact that the semaphore lever is
unlocked. The apparatus at each station is designed to be placed in an iron box
built on the semaphore lever stand, and of sufficient strength to stand the pull of
the lever.
In displaying the stop signals from a central office, which involves a reversal of
the operation of actuating the danger signals, I preferably use a local attachment
or annunciator device, (not shown) which may be arranged to ring an alarm bell
when the signal falls to "danger," thus notifying the local operator who may be
asleep or out of the building.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is :
1. An electrical apparatus adapted for railroad block systems of signalling
between two or more offices or stations, comprising at each station a visual signal,
mechanism for locking the signal in normal position, an unlocking magnet adapted
to operate upon said locking mechanism and release the signal, an electrical
transmitter arranged in relation to the signal locking mechanism so as to operate
only when the signal mechanism at that station is placed in normal position; said
transmitter being placed in an electric circuit and controlling the unlocking magnet

page_text: circuit at the distant station so as to affect the distant magnet only, whereby the
signal at the distant station is adapted to be unlocked by the operator at the home
station and then only when the signal at the latter station is locked in normal
position, substantially as described.
2. In an interlocking block signalling system comprising two or more offices or
stations, a visual signal for each station, mechanism for locking the signal in
normal position, means for releasing the signal including a normally open local
circuit, an unlocking magnet placed in said circuit and adapted to unlock the
signal and a transmitting device placed in circuit with the line wire and controlling
the unlocking magnet circuit at the distant station so as to release the distant
signal only and means for preventing the operation of the transmitting instrument
at either station until the signal mechanism at the station whose transmitter it is
desired to operate is placed in normal position, whereby the signal at each station
may be unlocked by the operator at the distant station and then only after the
latter operator has placed his own signal in normal position, substantially as
described.
3. In an interlocking block signalling system comprising two offices or stations, a
semaphore lever at each station, a disk connected with said lever and adapted by a
partial rotation to shift the signal; said disk being provided with a transverse
opening through the same, a plunger-transmitter adapted to register with said
opening when the disk and signal lever are in their normal positions, an unlocking
magnet provided with an armature lever adapted to engage and lock the disk in its
normal position, and main and local circuit connections, whereby the signal at each
station is adapted to be unlocked from the distant station only when the working
plunger and disk occupy fixed positions relatively to each other, substantially as
described.
4. In a signalling system, a visual signal and means for locking the same in
normal position comprising a peripherally notched rotatory disk connected with the
signal lever and provided with a transverse opening through the same, an armature
lever adapted to engage the notch in said disk so as to lock the same against
rotation, an electro-magnet adapted to actuate said armature-lever, a plunger-
transmitter adapted to register with the opening in said disk only when the latter is
locked with the signal in normal position, and circuit connections substantially as
described, whereby the semaphore lever may be unlocked from a distant station
only when the signal and locking disk at such station are in their normal positions,
substantially as described.
5. The combination with the respective semaphores or signals of a signalling
apparatus, of a locking device consisting of a disk connected to the semaphore
lever, and adapted to be moved a part revolution; an armature adapted to engage
and lock said disk, and an electrical transmitting device adapted to operate only
when the disk is locked, substantially as described.
6. In a signalling system a visual signal provided with an operating lever, a disk
connected to said lever, and adapted by a partial rotation to shift said signal, means
for automatically rotating said disk, an electro-magnet whose armature is arranged
to engage said disk and thereby lock said signal in normal position, and a selecting
instrument adapted to respond to a predetermined arrangement of electrical
impulses for the purpose of unlocking the signal, in combination with an electrical
apparatus placed at a distance from said signal and adapted to transmit the
electrical impulses to which said selecting instrument may respond, substantially as
described.
7. A selecting or preparing instrument adapted to respond to a predetermined
arrangement of electrical impulses, and a transmitting device for transmitting said
impulses, in combination with a lock signal and means operated by the selecting
instrument to unlock the signal and means for preventing the operation of these
devices until the operator's signal is placed in normal position.
8. In a signalling system, a visual signal and means for locking the same in
normal position in combination with an electrical apparatus placed at a distance

page_text: therefrom, adapted to transmit electrical impulses and thereby unlock said signal,
and means to prevent the transmission of said unlocking impulses until the signal nt
the transmitting station is placed in normal position.
9. In a block system, a series of signals located at the end of each block, and
means connected with each of said signals to prevent the operator from working
his own signal, and provided with a locking device at each signal, in combination
with an electric selecting apparatus responding to a predetermined arrangement of
electric impulses, an electrical impulse transmitting instrument at a distant station
adapted to transmit said predetermined arrangement of impulses, and means for
preventing the transmission of said impulses until the signal at the transmitting
station is locked in normal position.
LADA
THEO. MºKENNA,
Agent.