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Патент USA US2122131

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June 28, 1938.
D. F. DE LONG.
2,122,131
CENTRALIZED TRAFFIC CONTROLLING SYSTEM FOR RAILROADS
Filed July_ 25, 1934
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June 28, 1938.
D. F. D: LONG
. 2,122,131
CENTRALIZED TRAFFIC CONTROLLING SYSTEM FOR RAILROADS
Filed Jqly 25‘, ‘1934
4 Sheets-Sheet ‘2
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ATTORNEY
June 28, 1938.
2,122,121
D. F. DE LONG
CENTRALIZED :TRAFFIC CONTROLLING SYSTEM FOR RAILROADS
Filed July 25, 1934
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June 28, 1938. ‘
2,122,131
D. F. DE LONG
CENTRALIZED TRAFFIC CONTROLLING SYSTEM FOR RAILROADS
Filéd July 25,’ 1934
4 Sheets-Sheet 4
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ATTORNiEY
Patented June 28, 1938
UNITE
2,122,131
CENTRALIZED TRAFFIC CONTROLLING
SYSTEM FOR RAILROADS
Darrol F. De Long, Rochester, N. Y., assignor to
General Railway Signal Company, Roches
ter, N. Y.
Application July 25, 1934, Serial No. 736,949
13 Claims.
(Cl. 17'7—3,53)
This invention relates to centralized trai?c
controlling systems for railroads and it more par
'ticularly pertains to the communication part of
such systems.
‘
The present invention contemplates a cen
tralized tra?ic controlling system in which com
munication is established between a central con
trol of?ce and a large number of outlying ?eld
stations by means of a communication system of
10 the selective coded simplex type. The switches
and signals at a plurality of stations located
along the railroad track are connected to the
control of?ce by means of a two-wire line circuit.
The switches and signals are under the super
15 vision of the operator at the control o?ice so that
the condition of such switches, signals and var
ious other tra?ic controlling devices at the distant
stations will be transmitted to the control o?ice
for providing the operator with the necessary in
20 formation for governing train movements.
In a
system of this type a series of impulses forming
a particular code combination is transmitted over
the line circuit for the selection of a particular
?eld station and the transmission of controls to
the selected station. Similarly, a series of im
pulses forming a particular code combination is
transmitted over the line circuit for the registra
tion of a ?eld ‘station in the control office and
the transmission of indications from the regis
30 tered station. The control circuits and the indi
cation circuits are so interrelated in the system
employed that controls and indications are trans
mitted on separate cycles of operation.
It is proposed to provide a line battery at the
09 Ul control o?ice with a mid-tap connected to one
line conductor and with the opposite terminals of
the battery selectively connected to the other line
conductor.
-
Either control impulses are transmitted from
40 the control o?ice or indication impulses are trans
mitted from a ?eld station during any particular
operating. cycle. The control impulses are made
distinctive by reason of their polarity for the
purpose of transmitting the desired control code
' combination.
The indication impulses are made
distinctive by reason of the strength of current
in the line circuit for each impulse and also by
reason of the length of time during which the
line circuit is energized for each impulse. There
fore the capacity of the system of the present in
vention for the transmission of indications is
double that for the transmission of controls.
The system is so organized that irrespective of
the simultaneous occurrence of controls and in
dications to be transmitted only one location is
effective to transmit impulses at any one time.
For example, the control office may transmit con
trol impulses over the line circuit during an oper
ating cycle and during this cycle all ?eld stations
are prevented from obtaining access to the com
munication circuit for transmitting indication
impulses. Likewise, when one of the ?eld stations
is transmitting‘ impulses to the control o?ice all
other ?eld stations are locked out and the cir
cuits are arranged to guard against the control
of?ce breaking in on the line during an indica
tion cycle. If there are several stored controls
and indications awaiting transmission at the end
of an operating cycle, the control of?ce is given
preference and the system functions to transmit
all of the waiting controls before a ?eld station
can obtain access to the line for transmitting in-'
dications.
_
The polarity of the impulses during the trans
mission of controls is determined in the control
office by selectively connecting the line battery to
the line circuit. For a control cycle the impulses
are all of comparativelyshort (normal) length
and comparatively weak (normal) strength. The
impulses during the transmission of indications
are of the same polarity, but are varied in length
and in the strength of current in accordance with
the code combination made up at the trans
mitting ?eld station. In other‘words the ?eld
station which is transmitting its indications is -
capable of selectively applying any one of four
different conditions to the line circuit during
each step. These four conditions are, ?rst, nega
tive, short, strong impulse; second, negative,
short, weak impulse; third, negative, long, strong
impulse, and fourth, negative, long, weak impulse.
The control oflice in transmitting controls is
capable of selecting only one of two di?erent con
‘ ditions to be applied to the line circuit for each
step, these conditions being (+) and (—).
These characteristic features of the present
invention will be explained more in detail in the
following description of one embodiment and
various other characteristic features, advantages
and ‘functions of the invention will be in part
pointed out and in part apparent as the descrip
tion progresses.
In describing the invention in detail reference
will be made to the accompanying drawings which _
illustrate one method of carrying out the inven
tion by way of example. The drawings illustrate,
in a diagrammatic manner. the apparatus and
circuits employed and for convenience in describ
ing the invention in detail those parts having
similar features and functions are designated in
5
2
2,122,131
the various views by like letter reference charac
ters, generally made distinctive either by reason
of distinctive exponents representative of their
location or by reason of preceding numerals rep
resentative of the order of their operation and in
which:—
Fig. 1 illustrates, in schematic form, the two
wire line circuit extending from the control of?ce,
through a ?rst ?eld station to the end ?eld sta
10 tion, with certain contacts and relays illustrated
to show the fundamental control of the line
circuit.
Figs. 2A and 23 (with Fig. 2B placed below
Fig. 2A) illustrate the apparatus and circuit ar
rangements employed at a typical control of?ce
embodying the present invention.
Fig. 3 illustrates the apparatus and circuit ar
rangement employed at a typical ?eld station
embodying the present invention.
The illustrations in the drawings are. sche
matic and abbreviated for the purpose of clear
ness and simplicity. The detailed operation of
the circuits may be conveniently followed by
placing Fig. 3 to the right of Fig. 2A and by
placing Fig. 2B below Fig. 2A, with correspond
ingly numbered lines in alinement.
The arrangement of those parts of the system
which are not illustrated in the drawings and
their cooperation and connection with the illus
30 trated portions will be set forth in the following
general description. After the general descrip
tion, a detailed description will be given of the
transmission of controls from the control of?ce for selecting a ?eld station and for operat
ing-control devices thereat. Likewise, a detailed
description will be given of the transmission of
indications from a ?eld station for registering
such station in the control o?ice and for there—
after selectively operating indication devices as
40 sociated with the registered station in the con
trol of?ce.
General description
The symbols (+) and (—) are employed to
A 31 indicate the positive and negative terminals re
spectively of suitable batteries or other sources
of direct current and the circuits with which
these symbols are used always have current ?ow
ing in the same direction. The symbols (3+)
and (3-) indicate connections to the opposite
terminals of a suitable battery or other direct
current source, which has an intermediate or
mid-tap (CN) and the circuits with which these
circuits are used may have current flowing in
one direction or the other depending upon the
particular terminal used in combination with
tap (CN).
For convenience in describing the operation of
the system, the two line wires connecting the
60 control oi?ce with the stations are identi?ed by
referring to them as the stepping line and the
return line. The stepping line is the line in which
the line relays at the of?ce and at the ?eld sta
tions are connected, as well as the impulsing
65 contacts of the impulsing relay located in the
control o?ice. This line conductor also contains
other contacts for starting purposes, the details
of which will be explained later. The stepping
line and the return line extend in series through
all of the ?eld stations and are tied together
at the end station.
In considering the organization of the line
circuit illustrated in Fig. 1 it will be understood
that additional ?eld stations may be connected
in the line between the control oiiice and the
?rst ?eld station or between the ?rst ?eld station
and the end ?eld station.
Control oj?ce equipment-The control o?ice
(see Figs. 2A and 213) includes a quick acting line
relay F of the polar biased-to-neutral type, which
has its contacts positioned to the right when a
(+) impulse is connected to the stepping line
in the control oi?ce and to the left when a (—’)
impulse is connected to the stepping line in the
control of?ce. A marginal line relay HL of the
neutral type is connected in series with line re
lay F in the stepping line, this relay having such
a value and adjustment that it is not picked up
when current is ?owing over the line circuit with
resistance unit R.2 at the ?eld station in circuit. 15
Relay BL is picked up when resistance unit R2
is short circuited, to provide a substantial in
crease in current ?ow in the line circuit. In
other words relay HL responds to a strong im
pulse vbut not to a weak impulse.
20
A quick acting line repeating relay FP repeats
each energization of the line relay F, irrespec
tive of the polarity which energizes relay F.
Slow acting relays SA and SAP are picked up in
sequence at the beginning of each cycleand are
dropped in sequence at the end of each cycle.
25
Relay SA has such slow acting characteristics
that it does not drop away between successive
.energizations of relay FP and consequently re
lays SA and SAP do not drop away during im
pulsing.
The impulses of a cycle of operations cause
the step-by-step operation of a stepping relay
bank, including relays 'IV, 2V, 3V, 4V, LV and
VP. Thisstepping bank is arranged to take one 35
step for each de-energized period of the line cir
cuit between impulses. In other. words the step
ping relays are picked up one at a time during
each “off” period. The half step relay VP shifts
its position during each “on” period. In this 40
description the de-energized period of the line
circuit is conveniently referred to as the “off”
period and the energized period of the line cir
cuit is conveniently referred to as the “on” pe
riod.
Impulsing relay E is controlled by the stepping
relay bank in such a way that it time spaces the
impulses in the line circuit in accordance with
the actual response of the stepping bank. Im
pulse repeating relay EP' is provided to measure
the length of the impulses in the line circuit and
thus functions to- register the two indication con
ditions provided by the short and long impulse
periods of the system.
vStarting relay STR is picked up at the start
of each control cycle and dropped at the end
of each control cycle. Relay STR remains down
during an indication cycle. Checking relay CK
is picked up at the beginning of a control cycle
and is dropped at the end of a control cycle. 60
Control relay C is momentarily picked up at the
beginning of both control and indication cycles.
The detailed operations of these relays will be
pointed out later in the description.
Polarity control relay D is of the polar mag 65
netic stick type and is for the purpose of se
lectively connecting the line battery LB to the
line circuit during the “off” periods, in prepara
tionfor energizing the line circuit with the prop
er polarity during the succeeding “on” periods. 70
Code determining relay CD is one of a bank of
such relays which are so interconnected that
the momentary depression‘ of a starting button,
such as SB, causes relay CD to be picked up for
initiating ‘the system into a control cycle. The
73
2,122,131
interconnection of the CD relays and the stor
ing relays (not shown), which function to store
the operations of the starting buttons and to
permit only one CD relay to be picked up at any
one time is immaterial to an understanding of
the end of a control cycle, but is not picked up
during an indication cycle. The ?eld station in
cludes a lookout relay LO1 which is picked up
at the station which is sending indications. As
will be later described, the circuits of this look
the present invention, although this feature has
out relay are so organized that the station near
been completely disclosed in the prior applica
est the control o?ice obtains access to the com
tion of N. D. Preston et al. Ser. No. 455,304 ?led
May 24, 1930, corresponding to Australian Patent
1,501 of 1931.
As typical of the control levers located in the
control o?ice, switch machine lever SML is shown.
This lever is for the purpose of governing the
track switch at the station corresponding to re
15 lay CD. It will be understood that additional
levers for controlling the signals at the stations
will be provided, but it is not believed necessary
to complicate the drawings by showing this ad—
ditional equipment, since the operation controlled
'20 , by lever SML is typical of the operations con
trolled by additional levers.
For the purpose of illustrating station regis
tration, a typical pilot arrangement is shown in
Fig. 23. Pilot relays IPT and ZPT are posi
tioned on the ?rst step of the cycle in accord
ance with the indications transmitted. Relay
IPT is vcontrolled over the length of time in
dication bus LTI and relay ZPT is controlled over
the strength of current indication bus SCI. It
will be understood that additional pilot relays
may be provided and connected on additional
steps, up to the point where suflicient codes for
station registration are obtained. Since bus LTI
can be conditioned in either one of two’ways and
35 since bus SCI can be conditioned in either one
of two ways, four different conditions for each
step are obtained. These four conditions posi
tion relays lPT and ZPT in their four di?erent
combinations.
Station relay IST is for the purpose of regis~
40
tering the station which positions relays IPT and
ZPT to the left on the ?rst step. This relay is
merely typical of a number of such relays which
would ordinarily be provided, one for registering
1.45 each individual station. Additional station re
lays would be connected to additional contacts of
the pilot relays in their various combinations.
Suitable indication storing relays such as IIR
and 21R are for storing the variousindications
from a registered ?eld station, after such a sta
tion has been registered in the control o?ice by
the energization of its station relay. It will be
understood that relays HR and HR are merely
typical of a number of such indication storing
relays which may be provided for storing all
of the indications transmitted from a registered
?eld station and that the contacts of these in
dication storing relays may be connected to lamps
or other indicating devices.
Field station equipment.-The ?eld station i1
lustrated in Fig. 3 includes a quick acting line
relay F1 of the biased-to-neutral polar type, ac
tuated to the right by (+) impulses applied to
the line circuit and to the left by (—) impulses.
.65 Quick acting line repeating relay FP1 of the neu
tral type repeats the impulses in the line cir
cuit, irrespective of their polarities. Slow act
ing relays SA1 and SAP1 correspond to similar
relays in the control office and are used to de
?ne the bounds of an operating cycle, since they
are picked up at the beginning of each cycle and
dropped at the end of each cycle.
Checking relay CK1 corresponds to the similar
relay in the control office and is picked up at
the beginning of a control cycle and released at
munication system when several stations have
simultaneous indications ready to transmit and
other stations are locked out.
Relay HL1 is the relay at the station for v‘vary
ing the current in the line circuit to provide a
choice of two conditions, by determining whether
the current in the line shall be strong or weak
in character. This relay is controlled on the
various steps of a cycle over the strength of
current indication bus SCI1. Relay P1 is pro
vided for determining the length of time during
which the line circuit shall be energized for pro~
viding the additional choice of two conditions,
that is, short and long impulses of current. This
relay is controlled on the various steps of a cycle
over the length of time indication bus LTI1. Im
pulse relay PL1 is for the purpose of impulsing
the line circuit during the transmission of in .25
dications.
A stepping relay bank including relays lvl,
2V1, 3V1, 4V1 and VP1 is provided which oper
ates in synchronism with the corresponding re
lay bank in the control o?ice, so that they take 30
one step for each “off” period for marking off
the steps of the cycle. Pilot relay IPT1 is con
trolled over control bus C'I'L1 on the ?rst step of
the cycle in accordance with the polarity of the
?rst impulse. On the second step of the cycle, 35
switch machine control relay SMRl is controlled
in accordance with the polarity of the second imi
pulse at the station selected by the pilot relay. It
will be understood that additional pilot relays
and additional control relays may be provided 40
and connected in an obvious manner as the size
of the system demands.
- .
Track switch TS1 is operated by switch ma
chine SM1 in accordance with the impulse re
ceived over the line circuit which positions switch
machine relay SMR1. The position and .the
locked and unlocked conditions of the track
switch are repeated by the usual switch repeating
relay WP1. This switch repeating relay picks up
its neutral contact when the associated track 50
switch is in either of its locked positions and
drops this contact when the switch machineis
unlocked. The polar contacts of this relay are
assumed to be positioned to the right when the
associated track switch is in its normal position
and to the left when the switch is in reverse.
The polar contacts of relay WPl are shown for
the purpose of indicating on the drawings that
this is the usual track switch polar repeater re
lay. The polar contacts of this relay may con 60
nect to indication channel circuits connected to
front contacts of the stepping relays, such as con
tacts I53 and E63 for example, for transmitting
indications representing the position of the track
switch. Since these additional indications will 65
be transmitted in a similar manner to other typi
cal indications controlled by back contacts I55
and IE6 of relays T1 and WP, it is believed un
necessary to illustrate or explain the circuits in
detail.
'
.
Suitable signals are also provided (not shown)
for governing trafiic over the track section illus
trated in Fig. 3 and their control is in accordance
with suitable automatic signalling, in cooperation
with manual signalling controlled over the com
70
4
2,122,131
munication system. Since this signal control is
accomplished on the various steps of the cycle
‘in a'manner similar to that shown for controlling
the switch machine operation, it is not believed
necessary to show this portion of the system.
Track relay T1 registers a change in the con
dition of the detector track section with which
this relay is associated. It is energized when
the track section is unoccupied and de-energized
10 when the track section is occupied. Change relay
OH1 is the relay which registers the change in
condition of any of the devices at the associated‘
station, which requires that the communication
system transmit indications to the control o?ice.
15 Although the circuit of relay CH1 is not shown
it will be understood that it is normally ener
gized and when relay WP1 or relay T1 change
positions, the circuit of relay CH1 is momentarily
interrupted so that it is de-energized to initiate
an indication cycle.
The detail operation relating to the manner
in which relay CH1 is controlled to store indica
tions for transmission on a subsequent cycle when
the line is in use, is explained in detail in De Long
25 et al., Patent No. 1,852,402, issued April 5, 1932.
Relay CH1 of Fig. 3 is assumed to be operated
in the same way that relay CH of this De Long
patent is operated.
It is believed that the nature of the invention,
its advantages and characteristic features may
be best understood by continuing the description
in a manner relating to the detailed operation of
the system.
Operation
35
With the system in its normal or period of
blank condition, the line circuit is normally ener
gized with (—) potential applied to line i I which
positions all of the line relays to the left. The
current flow under this condition. is of a compara
tively low value since all of the station line relays
are connected in series and resistance R3 at the
end station is in the circuit. When a station
obtains access to the line for transmitting its
indications, a resistance unit is connected in the
line circuit for maintaining the current ?ow at
this comparatively low value and during the
transmission .of indications this current flow can
be increased in Value by short circuiting the re
sistance unit.
50
A cycle of operations for the transmission of
controls is started by initially, momentarily
changing the (—) energization of the line circuit
to a (+) energization. A cycle of operations for
the transmission of indications is started by ini
55 tially de-energizing the line circuit, all of which
will be explained in detail.
Normal at rest conditions.—The line circuit is
normally energized from the (—) terminal of line
battery LB, contact 20 of relay D in its left hand
60 position, windings of relays F and HL, back con
tact 2! of relay C, front contact 22 of ‘relay EP,
back contact 23 of relay E, line conductor ll,
winding of relay F1, back contact mt of relay
L01 and through the other stations in series, in—
65 cluding the tie and resistance R3 at the end sta
tion and line conductor 10 to the mid-tap of
battery LB.
Relay D in the control oflice is normally posi
tioned to the left by means of a circuit extending
70 from (B-), back contact 24 of relay STR and
winding of relay D to (CN). Relay EP is nor
mally energized over a circuit extending from
(+) , back contact 25 of relay E and winding of
relay EP to (—) .
~75
Since relay F has its contacts normally posi
tioned to the left, a circuit is completed for nor
mally‘ energizing relay FP which extends from
(+), contact 26 of relay F in its left hand posi
tion and winding of relay FP to (—).
At the ?eld station in addition to relays WP1,
T1 and CH1 being normally energized as above
mentioned, relay FPl is normally energized over
a circuit extending from (+) , contact i2! of re
lay F1 in its left hand position and winding of
relay FP1 to (——).
10
Manual start.—With the system in its normal
condition, the operator can initiate a cycle for
the selection of a particular station and the
transmission of controls to that station. For ex
ample, if he desires to operate track switch TS1
from its normal to its reverse position he moves
the switch machine lever SML from its normal
to its reverse position and then actuates starting
button SE. The actuation of button SB while the
system is at rest causes the energization of relay 20
CD. Relay CD closes a circuit for picking up re
lay STR which extends from (+), back contact
l2 of relay SA, lower winding of relay STR and
front contact 2'! of relay CD to (—).
The actuation of relay STR closes a circuit for 25
actuating relay D to the right which extends
from B+, back contacts 30, 3|, 32, 33 and 34 of
relays l V, 2V, 3V, 4V and LV respectively, control
bus CTL, front contact 24 of relay STR and
winding of relay D to (CN). The shifting of 30
contact 20 of relay D changes the energization of
stepping line conductor II from (—) to (+)
which marks the beginning of the initiating
period. Therefore all line relays will be actu
ated to their right hand positions. During this 35
change in the positions of the line relay contacts,
the associated FP relays are momentarily de
energized but this operation is of no effect.
A circuit is now closed for picking up checking
relay CK which extends from (B+) contact 28 40
of relay Fin its right hand dotted position, back
contact 29 of relay SA and upper winding of relay
OK to (ON). Relay CK closes a stick circuit for
itself extending from (+), front contact [5 and
lower winding of relay OK to (—). It will be 45
noted that the energizing circuits of the two
windings of relay CK are in a direction to ener
gize both of these windings in aiding relation, as
indicated by the arrows associated with these
windings. Relay CK remains picked up through 50
out a control cycle and at its front contact 96
connects (+) to the winding of relay EP for
maintaining this‘relay energized during such a
cycle. Relay CK closes a stick circuit for relay
55
STR extending from (+), front contacts 91 and
98 of relays CK and STR respectively, upper
winding of relay STR and back contact 5! of
relay LV to (—).
A circuit is now closed for picking up relay C 60
which extends from (+), front contact 35 of
relay FP, front contact 36 of relay CK, back
contact 31 of relay SAP, back contact 38 of relay
SA and winding of relay C to (—). Relay 0
closes a stick circuit for itself extending from 65
(+), back contact 39 of relay SAP, front contact
159 and winding of relay C‘ to (—).
Relay C opens its back contact 2| which de
energizes the line to mark the beginning of the
conditioning “oif” period. The momentary en 70
ergization of ‘the line circuit just described is
the initiating period.
During this initiating
period the shifting of relay F1 at the ?eld sta
tion to its right hand position closes a circuit for
picking up relayrCK1 extending from (B+), con
5
2,122,181
tact I22 of relay F1 in its right hand dotted posi
tion, back contact I23 of relay SA1 and upper
winding of relay CK1 to (CN) . Relay 0K1 closes
a stick circuit for itself extending from (+) , front
» contact I 24 and lower winding of relay 0K1 to
(~—). The energization of both windings of relay
CKl is such that these windings aid as indicated
by the arrows. The pick-up of relay CKl opens
the circuit of relay LOl at back contact I4! so
that the ?eld station cannot obtain access to the
system after it has been initiated by the control
office.
When relay F is de-energized at the beginning
of the conditioning “off” period, the opening of
15 its contact 26 de-energizes relay FP which closes
tact I‘! of relay VP, back contacts I8 and 58 of
relays 4V and 2V respectively and winding of
relay IV to (—). Relay IV closes a stick circuit
for itself extending from (+), front contact I2
of relay SA, front contact 5'! and winding of re~
lay IV to (—).
When relay FP picks up at the beginning of the
?rst “on” period, a circuit is closed for picking up
relay VP which extends from (3+) , front contact
44 of relay IV, back contacts 185, 45 and ill of re 10
lays 2V, 3V and 4V respectively, lower winding of
relay VP and front contact Id of relay FP'to (CN) .
Relay VP closes a stick circuit for itself extending
cuit extending from (+), front contact 40 of
relay FP, front contact 42 and Winding of relay
from (+), front contact I2 of relay SA, front
contact 52 and upper winding‘ of relay VP to (—). 15
A circuit is closed for picking up relay E which
extends from (+) , front contact 48 of relay CK,
back contacts 50, 5! and 62 of relays 4V, 3V and
2V respectively, front contact 63 of relay IV, front
contact lit of relay VP and upper winding of re 20
lay E to (—). The opening of back contact 23
of relay E de-energizes the line circuit, since back
SA to (—.), so that relay SA closes a circuit for
now
contact
open.
‘I3 of relay CK in bridge of contact 23
a circuit for picking up relay SA extending from
(+), back contact 40 of relay FP, back contact
III of relay SAP and winding of relay SA to (—).
During the following impulses of the cycle, relay
20 SA is energized at each “on” period over a cir
picking up relay SAP which extends from (+),
25 front contact 43 of relay SA and winding of relay
SAP to (—). The opening of back contact 38 of
relay SA and back contact 39 of relay SAP de
energizes the pick-up and stick circuits of relay
C so that this relay drops its contacts. This
30 closes the line at back contact 2| to mark the
beginning of the ?rst “on” period.
At-the ?eld station, relay SA1 is picked up when
relay FPl is dropped during the conditioning pe
riod over a circuit extending from (+), back’
contact I25 of relay FP1, back contact I26 of relay
SAP1 and winding of relay SA1 to (—). Relay
SA1 remains picked up during the cycle over a
circuit including front contact I25 of relay PP1
and front contact I21 of relay SA1.
Relay SA1
closes a circuit for picking up relay SAP1 which
extends from (+) , front contact I28 of relay SA1
and winding of relay SAP1 to (—) .
_
extends from (+) , front contact I2 of relay SA, 1
back contact I3 of relay FP, front contact ll of
relay VP, back contact I9 of relay 3V, front con
tact 59 of relay. IV and winding of relay 2V to
(—). Relay 2V closes an obvious stick circuit for
itself at its front contact 56. The opening of
back contact 62 of relay 2V de-energizes relay E
and when its back contact 23 is closed the line
circuit is again energized.
‘ This marks the beginning of the second “on”
period which picks up relay FP. Relay VP is now
de-energized by means of a circuit extending
from (B-), front contact ll] of relay VP, front 40
contact 45 of relay 2V, back contacts 46 and 4'!
of relays 3V and 2V, lower winding of relay VP
It will be understood that the same operation
takes place at all other ?eld stations connected to
the line circuit as described in connection with
and front contact Id of relay HP to (CN). Cur
rent over this circuit through the lower winding
of VP ?ows in opposite direction to the above 45
the typical ?eld station illustrated in Fig. 3. The
energization of the line circuit during a ‘control
cycle is of comparatively low current value due to
the resistance unit R3 included in the‘ line circuit
result that relay VP drops its contacts.
at the end station and since no ?eld station can
50 condition the line by changing its resistance dur
ing the “on” periods of a control cycle, relay H11
in the control o?ice remains ole-energized. In
addition to this, the executing circuit controlled
by relay I-IL, including bus SCI, is opened at back
55 contact 50 of relay CK to prevent the energization
of the individual indication, circuits selected by
the stepping relay bank in the control of?ce.
Line impulsing and stepping relay operation.—
Although the description of the stepping and im
60 pulsing operations will be more particularly di
rected’to Fig. 2A, it will be understood that sim
ilar operations take place at the ?eld station il
lustrated in Fig. 3 and at other stations along the
~. line.
Contacts H2, H3 and H4 of relays SA1 and
PP1 correspond to contacts I2, I3 and III of relays
SA and PP in the control of?ce. With the un
derstanding that stepping occurs at the ?eld sta~
tions in synchronism with stepping in the control
‘ oflice it is believed unnecessary to describe this
operation in detail at the ?eld stations.
After relay SA picks up in the conditioning
“off” period, a circuit is closed for picking up re
, lay IV extending from (+) , front contact I2- of
is
This marks the beginning of the ?rst “off” pe
riod which results in dropping relay FP. A cir
cuit is now closed for picking up relay 2V which
relay SA, back contact I3 of relay FP, back con-
described stick circuit through the upper winding,
so that the two windings now oppose with the
Relay E
is now picked up over a circuit extending from
(+) , front contact 48 of relay CK, back contacts
60 and SI of relays 4V and 3V respectively, front
contact 52 of relay 2V, back contact 65 of relay
VP and lower winding of relay E to (—). The
opening of contact 23 of relay E de-energizes the
line circuit.
55
This marks the beginning of the second “off”
period which drops relay FP. A vcircuit is now
_closed for picking up relay 3V extending from
(+), front contact I2 of relay SA, back contacts
I3, I‘! and I8 of relays FP, VP and 4V respectively, 60
front contact 58 of relay 2V and winding of relay
3V to (—). Relay 3V closes an obvious stick
circuit for itself at its front contact 55. Relay‘ E
is now de-energized because the previously de
.
scribed energizing circuit through the-lower wind
65
ing of this relay is open at back contact SI‘ of
relay 3V. The closing of back contact 23 of
relay E energizes the line circuit.
This marks the beginning of the third “on”
period which picks up relay FP. A circuit is 70
nowclosed for picking up relay VP extending
from (3+), front contact 46 of relay 3V, back
contact 41 of relay 4V, lower Winding of relay VP
and front contact I4 of relay FP to (CN). Relay
VP closes its above described stick circuit by way 75
6v
2,122,131»
of its front contact 52. Relay E is now picked
up over a circuit extending from (+), front con—
tact 48 of relay CK, back contact (iii of relay 4V,
front contact 6! of relay 3V, front contact 64
of relay VP and upper winding of relay E to (—).
The opening of back contact 23 of relay E de
energizes the line circuit.
This marks the beginning of the third “off”
period which drops relay FP. A circuit is now
10, closed for picking up relay 13V which extends
from (+), front contact 12 of relay SA, back
contact [3 of relay FP, front contact ll of relay
VP, front contact i9 of relay 3V and winding of
relay 4V to (—). Relay 1W closes an obvious
15' stick circuit for itself at its front contact 55%.
Relay E is now de-energized because the above
described circuit including its upper winding is
open at back contact 60 of relay dV. The closing
of back contact 23 of relay E energizes the line
20
circuit.
This marks the beginning of the fourth “on”
period which picks up relay FP. Relay VP is
now de-energized by means of a circuit extend
ing from (B—), front contact ‘iii of relay VP,
25 front contact 41 of relay llV, lower winding of
relay VP and front contact M of relay F? to
(CN).
Relay E is now picked up over a circuit
extending from (+), front contact 48 of relay
CK, front contact 68 of relay 13V, back contact 65
30 of relay VP and lower winding of relay E to (—).
The opening of back contact 23 ‘of relay E de
energizes the line circuit.
This marks the beginning of the fourth “off”
period which drops relay FP. A circuit is now
35 closed for picking up relay LV extending from
(+), front contact l2 of relay SA, back contact
l3 of relay FP, back contact ll of relay VP,
front contact E8 of relay 4V and Winding of
relay LV to (—). Relay LV closes an obvious
stick circuit for itself at its front contact
The opening of back contact 5! of relay LV den,
energizes the stick circuit of relay STR and this
latter relay is released.
Since relay LV does not de-energize the above
described pick up circuit for relay E, this relay
remains picked up for a comparatively long in
terval of time and since the line circuit cannot
be energized with relay E picked up, relay FP
remains down for a comparatively long interval
of time so that relay SA drops away. The drop
ping of relay SA de-energizes the stick circuits
of all stepping relays and these relays are re
leased. Relay E is de-energized when all step
ping relays are restored to their normal positions.
The dropping of‘ relay E again energizes the
line circuit which results in picking up relay FP.
Relay SA cannot be energized at this time, since
its pick up circuit is open at back contact 40 of
relay FF and its stick circuit is open at front
contact d2 of relay SA. Relay SAP is de-ener
of relay FP1 remains down :for the long time
interval. Immediately after the end of this last
long “off”- period, the picking up of relay FP1
deeenergizes relay SAP1 at back contact I25, so
that this relay is daenergized. Relay CK1 is
de-energized when the normal (_) current is ap
plied to the line circuit for positioning relay F1
to the left, over a circuit extending from (B—),
front contact l3! of relay CKl, contact I22 of
relay F1 in its left hand position, back contact
N3 of relay SA1 and upper winding of relay CK?
to (CN). This circuit is effective to de-energize
relay CK1 by means of the differential action of
the windings.
,
.
Polarity selection of controZ impulses-Assum 15:
ing that the stepping relays pick up‘ as above de
scribed, the ?rst impulse applied to the line cir
cuit (after the initiating (+) impulse) is deter-,
mined by the connectionof code, jumper 66. For
example, with jumper 66 connected to (B-) as 20,;
shown in Fig. 2A the ?rst impulse applied to the
line circuit is (—) , as determined by relay D be
ing positioned to the left over a circuit extending
from (B—), jumper 6E, front contact 6‘! of relay
CD, front contact 30 of relay IV, back con 25,
tacts 3!, 32, 33, and 34 of relays 2V, 3V, 4V
and LV respectively, front contact 24 of relay
STR, and winding of relay D to (CN) . With con
tact 29 of relay D in its left hand position a (—)
impulse is applied to the line circuit during the
?rst “on” period.
In the event that jumper 66 is connected in its
alternate position to (B+), then the above de
scribed circuit would energize relay D to its right
hand dotted position for applying a (+) impulse 35,:
to the line circuit for the ?rst “on” period.
Similarly,‘ if thelsystem is of sufficient size addi
tional'stepping relays such as 2V, 3V and the like
will select additional code jumper connections
through contacts of the CD relay for providing 40
combinations of (+) and (——) impulses in the
line circuit on additional steps of the cycle. It is
believed that the typical example illustrated is
sufficient to indicate how this selection is made.
When the system takes its second step, relay 45
2V extends control bus C'I‘L through front con
tact‘ 68 of relay CD to switch machine lever SML.
If the contacts of lever SML are in a right hand
position as shown in Fig. 2A, (B+) is applied to
the winding of relay D which positions this relay
to the right for'applying a (+) impulse to- the line
circuit at the second step. In the eventthat con
tact T2 of lever SML is in its left hand dotted
position, then (B—) is: connected to the winding
of relay D which positions this relay to the left
for applying a (~) impulse to the line circuit on
the second step. When the system takes addi
tional steps of the cycle, relays 3V and 4V extend
the circuit of relay D by way of'front contacts of
gized by the opening of front contact $3 of relay
relay CD to other controlling devices, such as a
SA and the opening of back contact 40 of re
signal lever, which have not been shown but the
lay FP.
Relay CK is de-energized by means of ’
a circuit extending from (B—), front contact ‘ll
‘of relay CK, contact 28 of relay F in its left
hand position, back contact 29 of relay SA and
upper winding of relay CK to (CN). Since the
current ?ow through the upper winding is in the
opposite direction to that indicated by the arrow,
70' the two windings oppose with the result that
“ relay CK releases.
30.:
00,
operation of which will be obvious from the above
typical example. i
'
From the above it will be observed that dif-..
ferent code combinations comprising a choice of
two per step may be used for selecting ?eld sta
tions and for controlling devices thereat. The
choice is (+) or (—) for each step, as deter
mined by the: code jumper connections. and the 70
control lever positions.
'
As above mentioned, the ?eld station stepping
bank steps through the cycle in a similar manner
Transmission of controls-It will be assumed
that relay lVl at the station illustrated in Fig. 3
to that described in connection with the control
is picked up in synchronism with relay IV in the
o?ice. Relay SA1 is-dropped when contact I25
control o?ice. The (—) impulse applied toythe 1.5
2,122,131
line circuit on the ?rst
of relay F1 to the left.
actuating the contact
extending from (B-—),
step actuates the contacts
A circuit is now closed for
of relay IPT1 to the left
front contact I3! of relay
CKl, contact I22 of relay F1 in its left hand posi
tion, front contact I23 of relay SA1, front contact
I32 of relay CKl, control bus: CTL1, back contacts
I33, I34 and I35 of relays 4V1, 3V1 and 2V1 respec
tively, front contact l35 of relay IV1 and winding
10 of relay IPT1 to (CN).
It will be understood that the transmission of
a (+) impulse at the first step positions con
tact I22 of relay F1 to the right which applies
(B+) to the winding of relay IPT1 for positioning
this relay to the right. Thus a choice of two
selections is obtained on the ?rst step for position
ing relay IPT1 to either of its two positions.
Relay 2V1 is picked up between the ?rst and the
second “on” periods so that a circuit is closed
20 during the second “on” period for positioning re
lay SMR1 to the right. This circuit extends from
(B+) , contact I22 of relay F1 in its right hand
dotted position (because lever SlVlL caused a (+)
impulse to be applied to the line on the second
25 step), front contact I23 of relay SAl, front con
tact I32 of relay (3K1, back contacts I33 and I34
of relays 4V1 and 3V1 respectively, front contact
I35 of relay 2V1, contact I31 of relay IP'lT‘1 in its
left hand dotted position and winding of relay
30 SM'R1 to (CN).
Relay SMR1 actuates its. con—
tact I38 to the right for causing the switch ma
chine to actuate the track switch to its normal
position.
In the event that the second impulse in the line
35 circuit is (-—) , as determined by lever SML being
in its reverse (left hand dotted) position, then
relay F1 is actuated to the left for actuating relay
- 7
that the picking up of contact I20 of relay LO1
shifts the closed circuit of the stepping line from
its back contact, which leads through other ?eld
stations, to common line Ill by way of resistance
units R1, R2 and back contact I43 of relay PD.
The de-energization of the line circuit drops
line relays F1 and F which in turn drop their
associated FP relays. The dropping of relay
FPI .at the station closes a circuit for picking up
relay SAl which extends from (+) , back contact 10;
I25 of relay FPI, back contact I26 of relay SAP1
and winding of relay SA1 to (—). The picking
up of relay SAI closes a circuit at its front con
tact I28 for energizing relay SAP1.
-
The dropping of relay FP in the control o?ice 15.
effects the picking up of relays SA and SAP in
the manner described in connection with the
initiation of a control cycle. Relay C is picked
up when relay FP closes. its back contact 35 and
relay C sticks until relay SAP is picked up, after‘ 205
which it drops in the manner described in con
nection with a control cycle. Thus, the opening
of back contact 2i of relay C keeps the line cir
cuit open in the control o?ice until after relay
SAP has picked up, although this line circuit 25.
may be closed at the initiating station before
relay SAP1 is picked up as will now be described.
The picking up of relay SA1 while relay FP1 is
de-energized causes the picking up of relay IV1
over a circuit which is similar to the circuit in
the control oflice which causes the picking
up of relay IV. The picking up of relay IV1
de-energizes relay PL1 at back contact I46, so
that the line circuit at the initiating ?eld station
is closed at back contact I40 of relay PL1.
When relay 0 in the control office closes its
contact 2I, the line circuit is energized to mark
the beginning of the ?rst “on” period and the sys
tem will step through the cycle as previously de
scribed in connection with the transmission of 110.
controls. Relay L01 remains stuck up during
the cycle over a circuit extending from (+),
front contact I51 of relay SA1, front contact
SMR1 to its left hand dotted position, which closes
a circuit from (B—-) at contact I38 for position
40 ing the track switch to its reverse position.
The transmission of additional controls is ef
fective on succeeding steps of the stepping relay
bank at the ?eld station for selectively positioning . M2 and winding of relay L01 to (-).
other control relays similar to relay SMR1, the
Relay CK in the control of?ce is not picked up 45,
45 detailed circuits of which need not be shown for
during a cycle of this class. because relay F does
an understanding of the present invention.
not actuate its contact 28 to its right hand dotted
With the release of relays SA1 and SAP1 at the position before relay SA opens its back contact
?eld station, the stick circuits of the stepping 29. Relay STR is not picked up during a cycle
relays are deenergized so that these relays are of this class because relay CD does not pick up 50
50 restored to their normal positions. Relay IPT1
to close its front contact 2'! before relay SA opens
and relay SMR1 remain in their last actuated its back contact I2. With relay CK down, its
positions until shifted by the reception of a suc
back contact ‘I3 places a shunt around back con~
ceeding code.
tact 23 of relay E so that relay E is not effective
Automatic start.—The system may be initiated to impulse the line circuit during an indication
55 into a cycle of operations from its normal condi
cycle. As will be later described the normal im
tion by an automatic change in condition at a pulse periods (short) of such a cycle are pro
?eld station. Such an initiation may be due to vided by the ?eld station while the long impulse
a change in traffic conditions or to the operation periods are provided by relay EP in the control
of a traffic controlling device to anew position in of?ce.
'
60 response to controls received from the control
Since relay STR is not picked up during a cycle
of?ce.
of this class, relay D remains actuated to the left
Such change in condition at the ?eld station
illustrated in Fig. 3, for example, drops relay CH1
which closes a circuit for picking up relay L01 ex
65 tending from (+) , back contact I39 of relay CH1,
back contact l29 of relay SAP1, back contact I4I
of relay 0K1 and lower winding of relay L01 to
(~). Relay L01 closes a circuit for picking up
relay PL1 extending from (+_) , back contacts I43,
and VP1 respectively, back: contact I48 of relay
Pl, winding of relay PL1 and front contact‘ I49 of
relay L01 to (—).
The picking up of relay PL1 de-energizes. the
line circuit at back contact I40. It will be noted
for transmitting a series of (—-) impulses
throughout the cycle. Such a series of all (—)
impulses corresponds to a phantom code and does
not result in the selection of any station for con
trols.
.
It will be understood that other ?eld stations
located between the station which is transmitting
and the control office will also step through the
indication cycle but, since their lockout relays are
not picked up, their circuits are ineffective to
cause the operation of relays corresponding to
PL1, P1 and HR. Since the line circuit outward
from the transmitting station is open at back con-_ 75
8.
2,122,131
tact I20 of relay L01, the line relays at the out
ward stations will remain down throughout the
indication cycle. This results in the FP relays
at these stations dropping their contacts for
closing circuits which pick up their associated
SA relays. The SA relays at these stations close
circuits for picking up their associated SAP re
lays. The SAP relays stick over circuits similar
to that extending through back contact I25 of
10 relay FP1 and front contact I26 of relay SAP1.
Since the FP relays are not intermittently oper
ated, their'front contacts similar to I25 are not
closed for energizing the SA relays and since the
back contacts similar to I26. of relay SAP1 are
15 open the SA relays drop out. In brief the SA
relays are dropped and the SAP relays are stuck
up at the stations on the line beyond the trans
mitting station.
The ?rst stepping relay at these stations will
20 likewise be picked up upon the response of the
corresponding SA relays but will drop again fol
lowing its release. Therefore these distant sta
tions remain in the condition with their F and FP
relays down and the SAP relay picked up until
25 the end of the cycle at which time the line again
is energized. At this time the F and PP relays
pick up which de-energizes the circuits of the SAP
relays extending through their front ‘contacts
similar to I26.
30
Transmission of indications.—When relay L01
at the calling station (illustrated in Fig. 3) is
picked up‘, the line circuit will be de-energized
to mark the end of the ?rst “on” period by the
picking up of relay PL1 over a circuit extending
35 from (+), back contacts I43, l44‘and I45 of re
lays 4V1, 3V1 and 2V1 respectively, front contact
I 46 of relay IV1, front contact I41 of relay VP1,
back contact I48 of relay P1, winding of relay
PL1 and front contact I49 of relay L01 to (—-).
This is a short impulse, terminated at the ?eld
station by the picking up of relay PL1 and is of
such a duration that relay E in the controlo?ice
does not remain picked up for a su?icient period
of time to allow relay EP to drop. Therefore this
45 indication is executed by closing a circuit for ac
tuating relay IPT to its left hand dotted position,
which circuit extends from (B—), front contact
80 of relay E, front contact 8! of relay EP, length
of time indication bus L'I‘I , back contact 82 of re
50 lay CK, back contact 83 of relay FP, front con
tact 84 of relay VP, back contact 85~ of relay
3V, front contact 86 of relay IV and Winding of
relay IPT to (CN).
The alternate indication condition is provided
55 on the ?rst stepwhen jumper I50 at the ?eld
station is connected in its dotted line position
to (+). This closes a circuit from (+), jumper
I50, front contact ISI of relay IV1, back contacts.
I52, I53 and I54 of relays 2V1, 3V1 and 4V1 re
60
spectively, length of time indication bus LT-ll,
winding of relay P1 and front contact I55. of
relay L01 to (—> .
The opening of back contact
I48 of relay P1 prevents the .pickingup of relay
65 PL1 for terminating the “on” period. Therefore
the line will remain energized with relay E‘ in the
control o?ice picked up for a su?iciently long
period of time to drop relay EP. The dropping
of relay EP de-energizes the line at its front.
70 contact 22 so that the system takes‘ its next‘step.
This indication‘ condition. is executed by posi
tioning relay IPT to the right over the previously
described circuit, which now extends ;from-(B+)
at back contact M of relay‘EP. During an in--'
76 dication‘cycle, relay CK is down and the (+9 for
operating relay E is supplied from back contact
99 of relay LV.
The above example indicates how the two in
dication conditions controlled by the length of
animpulse are obtained. It will be obvious that
these two conditions of the line circuit can be
obtained at. additional steps of the cycle in a
similar ,manner'when the system is of such a size
as to warrant additional code jumpers similar
to I50. It will be noted thatcontacts I43, I44, 10
I45, I46; and I4] of the stepping relay bank at
the ?eldstation are so arranged that a selective
circuit is made up for relay PL1 to terminate
the impulse period of each step, provided back
contact I48 of. relay P1 is closed. Since relay P1
is controlled in accordance with a selection of
two conditions, it will be apparent that the call
ing ?eld station can terminate each impulse
period by de-en'ergizing the line circuit, or it can
leave the line circuit energized at the ?eld sta
tion and ‘wait until the control o?ice terminates
an impulse period, which latter condition results
in. a long impulse.
It will now be explained how the strength of
current indication condition is effected. When
relay. IV1 at the calling station is picked up
and with code jumper I60 in the position shown,
relay I-IL1 remains down so that the line circuit
is energized in series with resistance unit R2.
This line circuit alsoincludes resistance unit R1
for the purpose of compensating for the resistance
of the line extending outward from the calling
station, which is removed when relay L01 is
picked up. With resistance R2 included in the
line circuit, a comparatively weak current flows
which is insu?icient to pick up relay HL in the
control office. This condition is executed in the
control o?ice over a circuit extending from (B—) ,
back contact ‘I4 of relay HL, strength of current
indication bus SCI, back contact 50 of relay CK, 40
front contact 15 of relay FP, back contacts 16,
TI. and ‘I8 of relays 4V, 3V and 2V respectively,
front contact ‘I9-of relay IV andvwinding of relay
ZPT to (CN). Current ?ow in this circuit is
effective to position the contacts of relay ZPT to
the left.
In the event that jumper I66 of Fig. 3 is con
nected in its dotted line position to (+), then
relay HL1 is picked up for short circuiting resist
ance R2 at its front contact I30. This allows a
comparatively strong current to ?ow over the
line circuit which picks up relay HL. Relay HL
closes its front contact 69 which short circuits
its lower winding to render this relay slightly
slow in releasing, for the purpose of maintaining 55
its front contact ‘I4 closed until after relay FP
drops its .front contact 15 at the termination of
the impulse period. This impulse condition is
executed by. connecting (13+) at front contact
‘I4 of relay HL over the above described circuit 60
to the winding of relay 2PT. which positions this
relay to the right.
It is believed that the above typical example
indicateshow achoice of two indications are ob
tained by iinpulsing the linecircuit With weak or 65
strong impulses. These two indication condi
tions, plus the .two previously described length
of time indications, provide a choice of four in
dication:conditions for'each step of the cycle.
With relays ‘IPT and 2PT positioned to the 70
left, .a circuit is .closed. for picking up relay IST
after relay. 2V. isvoperated, which circuit extends
from (+), back contact 87 of relay CK, front
contact-880i relay. 2V, front contact .89 of relay
F15’,v contact 90 ‘of relay IPT in its left hand ‘dotted 75
2,122,131‘
position, Contact SI‘ of relay ZPT in its left hand
energize switch machine indication lamps when
dotted position and winding of relay IST .to (—) .
Relay lST closes a stick circuit for itself ex
tending from (+) , back contact 8'! of relay CK,
in this position.
front contact 88 of relay 2V, front contact 92
and winding of relay IST to (—) . This stick cir
cuit maintains relay IST picked up until the end
of the cycle, when relay 2V opens its contact 88.
'
H 9
It will be understood that four di?erent com
binations of relays IPT and 2PT are obtained
on the ?rst step in accordance with the four in
dication conditions above described. All of these
four different combinations can be used for se
lecting individual station relays, one of which is
15 indicated by the selection of relay HST. Another
1.0
is obtained by relay IPT positioned to the right
and relay 2PT positioned to the right for one
combination. Relay IPT positioned to the left
and relay 2PT positioned to the right is for an
20 other combination. Still another combination
is with relay IPT to the right and ZPT to the
left.
It will be obvious that additional steps of the
cycle may be used for positioning additional pilot
25 relays, so that 16 combinations may be obtained
onltwo steps, etc.
'
Indications from registered stati0n.—-When the
line circuit is energized, after the station has been
registered in the control office as above described,
30 indication storing relays such as relays IIR and
21R of Fig. 2B are selectively actuated in accord
ance with the positions of relays at the calling
station, such as relays WP1 and T1 of Fig. 3.
For example, with relay T1 energized the sec
ond
impulse of the cycle is a weak impulse be
35
cause there is no circuit completed for picking
up relay EU to short circuit resistance unit R2..
This results in relay HL remaining down so. that
a circuit is closed for positioning relay IIR to
40 the left, which circuit extends from (B—), back
contacts ‘M and 5B of relays HL and CK re
spectively, front contact 15 of relay FP, back
contacts 76 and ‘H of relays 4V and 3V respec
tively, front contact 18 of relay 2V, front con
tact 93 of relay IST and winding of relay IIR
45
to (ON). Relay IIR may have its contacts ar
ranged to de-energize a track occupancy lamp
under this condition.
If relay T1 is de-energized, then relay HL1
50 is picked up- over an obvious circuit including
back contact I56 of relay T1. This results in
short circuiting resistance unit R2 for picking up
relay HL on this step, so that relay IIR is actu
ated to the right over the above described cir
55 cuit which now extends from (B+) at front
contact ‘M of relay l-IL. Relay IIR may have its
contacts arranged to energize a track occupancy
lamp when it is positioned to the right.
A choice of two other codes can be trans
60 mitted on this same step, which for example has
been shown in connection with relay WP1. With
this relay picked up there is no circuit for ener
gizing relay P1, 'therefore relay PL1 picks up and
de-energizes the line before the control oflice de
65 energizes it. This prevents the dropping of relay
EP in the control oflice. A circuit is closed for
positioning relay 21R. to the left which extends
from (B-), front contact 80 of relay E, front
70 contact 8! of relay EP, back contact 82 of relay
CK, back contact 83 of relay FP, back contact
84 of relay VP, back contact 94 of relay 4V’,
front contact 95 of relay 2V, front contact 96
of relay [ST and winding of relay 21R to (CN).
75 Relay 21R may have itsv contacts arranged to
~
In the event that the switch machine is un
looked, a circuit through back contact I66 of
relay WP1 is effective to pick up relay P1 for pre
venting relay PLl picking up and de-energizing
the line at the ?eld station.
This means that
the line will remain energized until relay EP ole-v
energizes it in the control o?ice. This closes
an executing circuit for actuating relay HR to 10
the right, which circuit is the same as previously
described except that it now extends from (3+)
at back contact 8! at relay EP. With relay 21R
positioned to the right, switch machine indicat
ing ‘lamps may be de-energized for indicating 15
that the track switch is in its unlocked condition.
It will be obvious that other indications may
be transmitted, such as signals clear and signals
at stop in the same manner described in con
nection with the switch machine. It is there 20
fore believed unnecessary to continue the dc;
scription for additional steps of the cycle, since
these additional steps effect the transmission of
indications in a manner similar to that already
25
described.
Pluralz'ty of stored start conditions.—In the
event of several stored oliice and ?eld start con
ditions, the system functions to send controls
until all stored controls have been taken care of.
After this the system is used for the transmis 30
sion of indications on separate cycles until all
indications have been taken care of. Assuming
that there are more than one stored office ‘and
?eld start conditions, there will be more‘ than
one storing relay in the control of?ce picked up, 35
so that when relay CD of Fig. 2A is dropped at
the end of a cycle a similar relay is picked up to
close a circuit similar to that extending‘ from
(—), front contact 21 of relay CD, lower wind
ing of relay STR and back contact E2 of relay 40
SA to (+). This picks up start relay STR, for
establishing the above described circuit from
(B+) at back contact 30 of relay lV (when all
stepping relays have dropped), to relay D for
positioning contact 28 of this relay to the right. 45
This is effective to initially energize the line ‘cir
cuit with a (+) impulse which marks the suc
ceeding cycle as one for the transmission of
controls.
The ?eld stations with stored start conditions
have their CH relays dropped butthe circuits
are not completed for picking up the lookout
relays at the stations, because under this condi
tion the SAP relays at the stations do not drop
their contacts similar to I29 for completing the
circuits to the lookout relays. This is because
the dropping of relay SA in the control oi?ce
allows a control start condition to be established
as above pointed out, before the SAPrelays at
the stations are dropped and since this control
start condition is effective to energize the line
with a (+) impulse, the checking relays similar
to relay CKl are picked up which also opens
the circuits of the lookout relays at back con
tacts similar to Hll. Therefore, as long as stored 65
oflice start conditions exist the system will con
tinue operating through cycles for the transmis
sion of controls without allowing a ?eld station
to break in until all controls have been taken
care of.
.
70
The communication system functions as abov
described to transmit the proper controls as de
termined by the particular CD relay which is
picked up. Should there be a plurality of ?eld
stations with indications to transmit when there
75
10
2,122,131
are no controls awaiting transmission, these sta
tions transmit their indications in rotation with
the station nearest the office having preference.
Lockout between ?eld sitations‘.—Assuming
that two change relays are dropped at approxi
mately the same time, the corresponding LO re
lays Will be picked up. Assuming that the sta
tion illustrated in Fig. 3 is one of the two having
indications ready for transmission at approxi
mately the same time, it will be noted that the
opening of back contact I26] of relay LO1 pre
vents the energization of the line circuit outward
from the station illustrated in Fig. 3.
The picking up of relay L01 energizes the'line
15 inward towards the control office, since the con
tinuity of the line is established through front
contact I20 of relay L01, resistance units R1
and R2 and back contact I40 of relay PLl. This
closed circuit is immediately interrupted how
20 ever
because relay PL1 picks up over the
previously described circuit including front con
tact I49 of relay L01. This de-energizes the
line for initiating the system, as previously de
scribed in connection with an indication cycle.
25 Relays F1, FPl, F and FF are dropped and re
lays SA1, IV1, SAP1, SA, SAP and IV are picked
up as previously described. Relay C is also
picked up and dropped and when its back con
tact 2I is closed, back contact I40 of relay PL1
30 will be closed so that the line circuit is again
energized.
The picking up of relay SA1 closes a stick cir
cuit for relay LOl extending from (+), front
contact I57 of relay SA1, front contact I42 and
I winding of relay L01 to (—-). Therefore relay
L01 remains stuck up throughout the cycle and
at its front contacts I49, I55 and I65 the indica
tion conditioning circuits are completed as above
described.
40
At the station farther out the line attempting
to transmit, the line relay and line repeating
relay are dropped which picks up the SA and SAP
relays in sequence. As soon as the SAP relay at
this inferior station is picked up, the pick up cir
45 cuit of the SA relay is opened at a back contact
similar to I26 and since the FP relay is down,
the stick circuit of the SA relay is open at a front
contact similar to I25. This results in the SA
relay dropping its contacts, so that there is no
50 stick circuit for holding the lookout relay at a
’ front contact similar to I 5'! and since the pick up
circuit of the lock out relay is open at a back con
tact similar to I29, this relay is dropped. At
the end of the cycle, when the line circuit is again
55 energized the F, FP and SAP relays at the in
ferior station are restored to normal as already
described in connection with the description of an
indication cycle. At the inferior station, when
the SAP relay closes its contact similar to I29 this
60 station can obtain control of the communication
system, provided no other, superior station is
waiting with a stored start condition.
In connection with ?eld start conditions which
occur in sequence, it will be noted that the dead
, line for picking up a lookout relay is at the time
when the SAP relay opens its back contact I29.
Therefore, any station which initiates a cycle
sufficiently in advance of a changed condition
occurring at another station for the ?rst station
- to pick up its SAP relay, will obtain access. to the
communication system and lockout all other sta
tions. It is believed that the above example re
lating to two simultaneous start conditions and
the statement regarding sequential starting con
75 ‘
ditions are sufficient to convey a proper under
standing of‘the' lockout feature of the present in
vention.
‘
Having thus described one speci?c embodiment
of a centralized traf?c controlling system, it is
desired to be understood that the particular ar 5
rangements illustrated and suggested are only
typical of applicant’s invention and are not in
tended to indicate the exact circuit design and
speci?c arrangement necessary to carry out the
features of the invention. This particular form 10
has been illustrated to facilitate in the disclosure,
rather than to limit the number of forms which
the invention may assume and it is further de
sired to be understood that various modi?cations
may be made in order to meet the various prob 15
lems encountered in practice, the system may be
varied in the number of ?eld stations to which the
invention is app-lied and the amount of apparatus
at each ?eld station may be varied to suit local
conditions, all without in any manner departing
from the spirit or scope of the present invention,
except as limited by the appended claims.
-What I claim is:—
1. In a centralized tra?ic controlling system, a
plurality of locations including a control o?ice
and a plurality of ?eld stations connected by a
line circuit, control transmitting means in said
of?ce for intermittently and reversibly energizing
said line circuit during an operating cycle of said
system from a source of current at said o?ice for 30
providing a ?rst series of polar impulses, indica
tion transmitting means at each of said stations
for intermittently and distinctively energizing
said line circuit during an operating cycle of said
system from said source of current for providing a
second series of distinctive impulses, means at
said office for selecting the polarity of each of
said ?rst series of impulses in accordance with
predetermined codes, means at said stations re
sponsive only to said ?rst series of impulses, 40
means at said o?ice responsive only to said second
series of impulses, and means for rendering said
control transmitting means superior to said indi
cation transmitting means.
2. In a centralized traffic controlling system; a 45
control office and a plurality of ?eld stations con
nected by a line circuit; means for intermittently
energizing said line circuit from a source of cur
rent for providing series of impulses; means at
said o?ice for causing the impulses of one series 50
to be of a ?rst and a second character to char
acterize a control code; means at said o?ice for
causing each of the impulses of another series
to be of said ?rst character to characterize a non
control code; means at each of said stations for 55
characterizing the impulses of said another series
as to constitute impulses of a third or fourth
character to characterize an indication code;
and means for preventing the energization of said
line circuit with an impulse of said fourth char 60
acter during a control code series in which said
line circuit is energized with impulses of said ?rst
and second characters.
3. In a centralized trai‘?c controlling system, 65
a control o?ice and a plurality of ?eld stations
connected by a line circuit, means for transmit
ting a plurality of series of current impulses of
Variable polarity in one direction over said line
circuit, means for transmitting a plurality of 70
series of current impulses of variable length and
variable strength in another direction over said
line circuit, and means for preventing the trans
mission of a series of variable length and variable
strength impulses as long as a condition exists
2,122,131
requiring the transmission of variable polarity
impulses.
4. In a remote control system, a line circuit
over which .a plurality of series of impulses are
transmitted, a line relay at each end of said line
circuit responsive to said impulses, an impulsing
relay and a timing relay at the impulse trans
mitting end of said line circuit, means rendering
said impulsing relay effective to transmit said
plurality of series of impulses, means rendering
said timing relay ineffective to time the impulses
8. In a remote control system; a transmitting
station and a receiving station connected by a
line circuit; means at said transmitting station
for applying a ?rst and a second series of spaced
impulses of current to said line circuit;
im
pulse receiving relay actuated from one position
to another in response to said impulses; a nor
mally energized and picked up slow release relay
for opening said line circuit when deenergized;
means controlled by said impulse receiving relay,
of a ?rst series, means responsive to the impulses
and including the line relay at the transmitting
end of said line circuit for timing the impulses
15 of said ?rst series, and means including the line
relay at the receiving end of said line circuit
for rendering said timing relay effective or in
effective to time said impulses of a second series.
5. In a remote control system, a line circuit
20 over which a plurality of series of impulses are
transmitted, a line relay at each end of said line
circuit responsive to said impulses, an impulsing
relay and a timing relay at the impulse trans
mitting end of said line circuit, means rendering
25 said impulsing relay effective to transmit said
plurality of series of impulses, means rendering
said timing relay ineffective to time the impulses
of a ?rst series, means responsive to the impulses
and including the line relay at the transmitting
end
of said line circuit for timing the impulses of
30
said ?rst series, means including the line relay
at the receiving end of said line circuit for ren—
dering said timing relay effective or ineffective
to time said impulses of a second series, and
and effective if it remains in said another posi
tion for more than a predetermined time interval,
for releasing said slow release relay to cause each
impulse to be rendered normally long; a series
of polar indication relays, one for each impulse 15
of said ?rst series; means rendered effective each
time said impulse receiving relay is actuated to
said one position for energizing one of said in
dication relays to one position provided said slow
release relay is then picked up and to another
35 means controlled by the line relay at the trans
mitting end of said line circuit for registering the
lengths of the impulses of said second series.
6. In a remote control system; a line circuit;
a line relay connected to said line circuit; means
for energizing said line circuit with a ?rst series
of time spaced impulses of current of normally
short and abnormally long lengths, whereby said
line relay is intermittently operated and re
leased; a slow release relay; means including said
line relay for maintaining said slow release relay
picked up as long as said impulses are normally
short and for releasing said slow release relay
when any one of said impulses is abnormally
long; means controlled by the release of said
slow release relay for rendering an impulse
50 abnormally long; and additional means for main
taining said slow release relay picked up irre
spective of the length of the impulses, whereby
a second series of all normally short impulses is
applied to said line circuit.
'7. In a remote control system; a line circuit;
a line relay connected to said line circuit; means
for energizing said line circuit with a ?rst series
of time spaced impulses of current of normally
short and abnormally long lengths, whereby said
60 line relay is intermittently operated and released;
a slow release relay; means including said line
relay for maintaining said slow release relay
picked up as long as said impulses are normally
short and for releasing said slow release relay
65 when any one of said impulses is abnormally
long; means controlled by the release of said slow
release relay for rendering an impulse of said
abnormal time interval; additional means for
maintaining said slow release relay picked up ir
respective of the length of the impulses, whereby
a second series of all normally short impulses is
applied to said line circuit; and means controlled
75
11
by said slow release relay for registering said
normal and abnormal time interval impulses.
position provided said slow release relay is then
released; means at said receiving station for at
times opening said line circuit to cause said im
pulses to be abnormally short, whereby said im
pulse receiving relay is actuated to said another 25
position for a time less than said predetermined
time interval; and additional means at said
transmitting station for maintaining said slow
release relay picked up throughout said second
series of impulses and for causing said second
series of impulses to be invariably normally short.
9. In a code communication system for trans
mitting controls from a control office to a ?eld
station and for transmitting indications from the
?eld station to the control office, a line: circuit in 35
cluding a source of energy at the control office
and connecting the control office and the ?eld
station, transmitting means at the control office
effective when initiated to energize said line cir
cuit from said source with a series of time spaced
impulses, each having a selected polarity, means
for energizing said line circuit from said source
with one polarity when said office transmitting
means is inactive, transmitting means at the
?eld station effective when initiated to cause the 45
opening and closing of the line circuit for rela
tively long and short periods of time to form
successive series of time spaced impulses, means
for initiating said transmitting means at the
?eld station only if the line circuit is energized 50
with said one polarity and only if said control
of?ce transmitting means is inactive, means at
the control office for applying the opposite polar
ity to the line circuit at the end of any series of V
impulses transmitted from the ?eld station, and 55
means for initiating said transmitting means at
the control office when said opposite polarity is
applied, whereby the transmitting means at the
control o?ice can interrupt the transmitting
means at the ?eld station at the end of any series 60
of impulses effected by the ?eld station.
10. In a code type communication system; a
line circuit connecting a control office and a
?eld station and including a source of energy at
the control office; a transmitter at the control 65
office effective, when set into operation, to ener
gize said line circuit with a series of time spaced
impulses of polarities selected in accordance with
controls to be transmitted; a transmitter at the
?eld station effective when set into operation to 70
open and close said line circuit for a series of
relatively short and long time periods in accord
ance with indications to be transmitted; initiat
ing means at the control office for setting said
transmitter at the control office into operation 75
12
2,122,131
when such initiating means is rendered‘ active;
manually operable starting means in the control
oi?ce for rendering said initiating means active;
means at the control office for energizing said
line circuit with a particular polarity when said
initiating means is inactive and for energizing it
With the opposite polarity when said initiating
means is rendered active; a changeable device at
the ?eld station; initiating means at the ?eld
station for setting the transmitter at its station
into operation when such initiating means is
rendered active; and circuit means effective upon
a change in said device, only if said line circuit
is energized with said particular polarity, to ren
der said initiating means at the station active.
11. In a code communication system of the
character described for transmitting controls
from a control oi?ce to a ?eld station and for
transmitting indications from the ?eld station to
20 the control o?ice, a line circuit connecting the
control of?ce and the ?eld station, a source of
energy at the control office, a transmitter at the
control o?ice operable to energize said line cir
crating cycle for the transmission of controls,
means in the control o?ice including said source
for energizing said line circuit with one polarity
whilethe system is at rest and responding to
operation of said manual starting means to
change the energization of the line circuit to the
other polarity, and equipment at each ?eld sta
tion comprising, a changeable device having dif
ferent conditions to be indicated in the control
o?ice, sectionalizing, means responsive to a change 10
of condition of said device for terminating said
line circuit at the corresponding station, means
responsive to the energization of said line circuit
with said other polarity prior to the energization
of said cycle marking means for preventing oper 15
ation of said sectionalizing means, a code trans
mitter, and means responsive to the ?ow of cur
rent in said line circuit in the corresponding sta
tion after operation of said sectionalizing means
for rendering the code transmitter at that sta 20
tion effective during the ensuing cycle to open
and close said line circuit to form an indication
code characteristic of the station.
cuit from said source with different series of >
13. In a remote control system; a line circuit
time spaced impulses only if the ?eld transmitter connecting
a control oflice and a ?eld station; a
is inactive, each of said impulses being of one control o?ice line relay and a ?eld station line 25
selected polarity or the other in accordance with relay connected in series in said line circuit;
a code, means for energizing said line circuit means at thecontrol o?ice including a source of
from said source with a particular polarity when
energy for initially energizing said line circuit;
30' said o?ice transmitter is inactive, a transmitter
transmitting means at the ?eld station operat 30
at the ?eld station operable to open and close ing, when active, in response to each energiza~
the line circuit for relatively long and short tion of said line relay for opening said line circuit
periods of time to e?ect the energization of the after a short period of time and then re-closing
line circuit with successive series of long and the line circuit or operating to leave it closed until
short time spaced impulses, only if said trans
the next impulse period; a slow release relay at
mitter at the control o?ice is inactive and said the control o?ice; means responsive to each ener 35
line circuit is energized with said particular po
gization of said control o?ice line relay for main
larity, and means at the control oi?ce for ren
taining said slow release relay picked up for each
dering said transmitter at the ?eld station in
short impulse period but allowing it to drop away
active at the end of any series of impulses trans
for an abnormally long impulse period; means
mitted from the ?eld station to allow the oper
including said slow release relay for terminating
ation of said transmitter at the control o?‘ice by an abnormally long impulse period and then re
applying a polarity different from said particular
polarity, whereby the transmission of controls
from the control oi?ce is given superiority over
the transmission of indications from the ?eld
station.
12. In a system of code communication between
a control o?ice and a plurality of ?eld stations,
a single line circuit connecting the control o?ice
and the several ?eld stations, a source of energy
at the control o?ice cycle marking means in the
control o?ice and at each ?eld station assuming
its normal condition at the end of an operating
L1 El cycle in response to a prolonged deenergization
of said line circuit, manually operable starting
means in the control oi?ce for initiating an op
closing the line circuit; whereby said line circuit
is energized with impulses of normal and abnor
mal length as determined by said transmitting
means at the ?eld station; cycle checking means 45
at the control office and at the ?eld station acting
at times to render said transmitting means at
the ?eld station inactive to maintain said line
circuit closed and for maintaining said slow re
lease relay at the control oi?ce picked up irrespec 50
tive of the length of the impulses on said line cir
cuit; and means at the control o?ice operating
when said cycle checking means is active to im
press impulses or normally short time periods on
55
said line circuit.
DARROL F. DE LONG.
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