US2276680A - Railway traffic controlling apparatus - Google Patents

Description

March 17, 1942. E. M. ALLEN ,2 5 6 RAILWAY TRAFFIC CONTROLLING APPARATUS I Filed Jan. 13, 1940 2 Sheets-Sheet 1 Conzmlledbg liaoli Circuit nexz in advance.

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lliecggz d d I Appmaob "l v fedl'um Code I F1 1 .QSeoond -1 klsi'econd Clear Code 'J l l INVENTOR Earl lien. Fig 5 gawk HIS ATTORNEY.

March 17, 1942. E. M. ALLEN 8 RAILWAY TRAFFI IIC CONTROLLING APPARATUSv I Filed Jan. 13, 1940 2 Sheets-Sheet, 2

W v X UpJSeaond I 259mm? Up JSecond ZZSKUMJ v 2 50001212 I v A p bjbc'ana' Code LI T l LI L] L] m Approach m zlspmm I SZowC'adg n H H I1 Fl FT Medium C'ode l INV ENTOR H115 ATTORNEY Patented Mar. 17, 1942 OFFICE RAILWAY TRAFFIC CONTROLLING APPARATUS Application January 13, 1940, Serial No. 313,754

8 Claims.

My invention relates to railway traflic controlling apparatus, and particularly to apparatus for a railway signal system using coded energy having cyclic patterns of the time code type.

In time code systems it has been proposed to use slow release relays or slow pick-up relays or a combination of both as the decoding means, such relays responding in dififerent combinations to the diiierent lengths of the on and oil periods of the different codes. In decoding relays for such systems inaccuracy of operation due to variations of voltage of the current source and variations of the operating periods of the relays due to changes in the resistances of the relay windings because of varying ambient temperature must be compensated as well as the presence of the coded energy detected and the operativeness of the means used to provide the slow acting characteristics for the decoding relays checked.

Accordingly, an object of my invention is the provision of novel and improved decoding means for signaling systems using coded energy of the time code type.

Another object of my invention is the provior sion of novel and improved means for signal systems of the type here involved wherewith a short period present in each of the difierent codes serves to make available energy for operation of the decoding relays.

Still another object of my invention isthe provision of novel and improved decoding means for signal systems of the time code type which is substantially free from variations in its operation periods because of changes in temperature.

Again, an object of my invention is the provision of improved decoding apparatus for signal systems of the time code type wherein the presence of the means used to provide the slow acting characteristics of the decoding relays is checked.

Other objects and advantages of my invention as well as the above listed objects I attain by providing two reactance devices in which energy is alternately stored and released to control slow pick-up decoding relays, such reactance devices being preferably either condensers or inductors. Energy is stored in a selected one of such reactance devices during the on period of each code cycle and this stored energy is discharged to energize selected ones of a group of slow pick-up relays during the ofi period of each code cycle. Each of these decoding relays is provided with a preselected slow pick-up period and this stored energy is used during the on period of each code cycle-to energize other relays of the group of slow pick-up relays according to the duration of the on period of the particular code. The circuits are proportioned to charge the reactance devices quickly and to discharge the devices at a predetermined rate so that either device can be fully charged during the shortest code period used and either device can supply energy for the longest code period used. When condensers are used as the reactance devices, the condensers themselves if of the electrolytic type which have a negative temperature coeflicient of resistance serve to compensate for variations in the pick-up time of the slow pick-up relays due to variations of the resistances of the relay windings caused by changes in ambient temperature. If the reactance device is an inductor including a winding mounted on a magnetic core, then asymmetric units such as the copper oxide rectifier unit are provided to compensate for the variations in the pick-up time of the slow pick-up relays due to changes in temperature, since a copper oxide rectifier unit is characterized by a decrease in resistance in its forward direction when the temperature increases. When reactance devices are used as a secondary source of power in which energyis stored by operation of a code following relay and the energy stored in such reactance devices is used to energize decoding relays, operation of the code following relay is assured and false energization of any of the decoding relays because of a failure of the code following relay is avoided. To detect the presence of coded energy I provide a control relay having two windings one winding of which is energized along with certain of the slow pick-up relays by the energy stored in one of the reactance devices and the other of which windings is energized along with other ones of the slow pickup relays by the energy stored in the other reactance device. The slow pick-up characteristics of the decoding relays I obtain by including a resistor in series with the winding of each of the respective relays which resistor can readily be proportioned to give the desired pick-up period for the associated relay and the presence of which resistor is checked because the energizing current for the relay flows through the resistor. The signal operating circuits and other controlling circuits are governed by the two-winding relay and the group or series of slow pick-up relays according to the extent the slow pick-up relays are energized by the particular code.

I shall describe two forms of apparatus embodying my invention, and shall then point out the novel features thereof in claims.

In the accompanying drawings, Fig. l is a diagrammatic view showing one form of apparatus embodying my invention when used with a four-block five-indication wayside signal system for railways. Fig. 2 is a diagrammatic view showing a second form of apparatus embodying my invention when used with a four-block fiveindication wayside signal system for railways. Figs. 3 and 4 are views diagrammatically illustrating different time codes that may be used with the apparatus of Figs. 1 and 2, respectively.

In each of the different views like reference characters designate similar parts.

It is to be understood, of course, that my invention is not limited to a four-block five-indication wayside signal system and this one use serves to illustrate the many places wher apparatus embodying the invention is useful.

Referring to Fig. 1, the reference characters la and lb designate the traffic rails of a stretch of railway over which traffic normally moves in the direction indicated by an arrow, and which rails are formed by the usual insulated rail joints into consecutive track sections of which sections only the one full section W-X and the adjoining ends of the two adjacent sections are shown for the sake of simplicity.

Each track section is provided with a track circuit which comprises means for supplying coded energy to the rails at one end of the section and a code following track relay connected with the rails adjacent the other end of the section for operation of the relay by such coded energy, such coded energy having different cyclic patterns of the time code type and which cyclic patterns are selected in accordance with different traffic conditions.

The means for supplying coded energy to the track circuit for section WX includes a battery KB and a relay XR together with traffic controlled code transmitting circuits to be later described. At this point in the description it is sufiicient to say that when relay XR is picked up closing front contacts 4 and 5, the two terminals of battery XB are connected across the rails la and lb to supply current thereto and when relay XR is released opening front con- 1 tacts 4 and 5 and closing back contacts 6 and I, the battery XB is disconnected from the rails and the rails are short circuited. It follows that by operation of relay XR. according to a cyclic pattern consisting of a preselected period during which the relay XR is picked up and a selected period during which the relay is released, direct current of a time code corresponding to the cyclic pattern at which relay KR is operated is supplied to the track circuit of section WX.

At the left-hand end of Fig. 1 there is shown a medium and clear. In the diagrams the on periods of a code are represented by the raised portions of the curve and the off periods of a code are represented by the depressed portions of the curve. Under the first or approach traffic condition relay XR, for example, is operated in cycles during each of which it is picked up for substantially .3 second and released for substantially .1 second, and the coded track circuit current has a cyclic pattern consisting of an on period of .3 second and an off period of .1 second. Under the second or approach-slow trafiic condition, relay XR is picked up for .1

second and released for .3 second each operation cycle and the track circuit current has a cyclic pattern consisting of an on period of .1 second and an ofi period of .3 second. Under the third or approach-medium tramc condition, relay XR is picked up .1 second and released .9 second each operation cycle and the cyclic pat tern for the track circuit current has an on" period of .1 second and an 01f period of .9 second. Under the fourth or clear trafiic condition, relay X5. is picked up .9 second and released .1 second each operation cycle and the cyclic pattern for the track circuit current has an on period of .9 second and an off period of .1 second. As stated hereinbefore, relay WR is operated in a manner similar to relay XR to impress corresponding cyclic patterns on the current to the track circuit for the section next in the rear of section WX. The circuit means by which relays XR and WE ar operated in accordance with different traffic conditions to produce the time codes illustrated in Fig. 3 will appear as the specification progresses.

It is to be understood my invention is not limited to the cyclic patterns illustrated in Fig. 3 either as to the relative or as to the absolute durations of the on and off periods, and the relative as well as the absolute durations of the "on and off periods can be selected as desired within the operating limits of the associated decoding relays. The cyclic patterns illustrated in Fig. 3 are one selection that is satisfactory. It is to be observed that one or the other of the two periods of each of the four different cyclic patterns is relatively short and is of .1 second duration.

A code following track relay WTR is connected across the rails adjacent the entrance end of section W-X for operation by the coded current supplied to the track circuit of that section. Relay WTR is a direct current neutral relay of the usual type and hence is energized and picked up closing its front contacts 8 and 9 when current fiows in the track circuit during each on period and is released closing back contacts I0 and l I when no current flows during the off period of each code cycle. In other words, code following relay WTR is operated in step with the "on and off periods of the cyclic pattern of the different codes impressed upon the track circuit current.

Operation of code following track relay WTR causes energy to be alternately stored in and discharged from each of two reactance devices or condensers Cl and C2. With relay WTR released closing back contact Hi, condenser Cl is connected with a source of direct current whose terminals are indicated at B and C and condenser Cl is charged the charge buildin up rapidly. When relay WTR is picked up closing front contact 8, condenser CI is disconnected from the current source and connected with a relay energizing circuit to be later referred to and the condenser discharges the energy stored therein through such energizing circuit at a rate governed by the time constant of the circuit. When relay WTR. is picked up closing front contact 9, the condenser C2 is connected with the current source and condenser 02 is quickly charged, and then when relay WTR is released closing back contact H, the condenser C2 is discharged into another relay energizing circuit to be later referred to, at a rate governed by the time constant of the circuit. The energizing circuits into which the condensers Cl and Clare discharged include a check or control relay AH and a, group or series of slow pick-up relays which in Fig. 1 comprise relays BI-I, AD and BD, relays BH and AD being controlled by the energizing circuit associated with condenser C2 and relay BD being controlled by the energizing circuit associated with condenser Ci.

Resistors RE, R2 and R3 are associated with relays Bi-I, AD and BD, respectively, by being interposed in series with the winding of the respective relay. Each of these resistors provides the desired pick-up period for the respective relay. As indicated in Fig. l, resistor R1 is proportioned to provide a .3 second pick-up period for relay BH and resistors R2 and R3 are proportioned to provide a .9 second pick-up period for relays AD and BD, respectively, such pick-up periods for relays BH, AD and 13D being selected to agree with the time codes illustrated in Fig. 3.

The check or control relay AH is a two-winding-relay and relay AH as well as the slow pickup relays EH, AD and B1) are all made slightly slow to release, the release period for relay AH being just suficient to bridge the intervals required for code following relay WTR to move between its front and back contacts, and the release periods of relays BH, AD and BD being just sufficient to bridge the relatively short .1 second period of the diiferent time codes.

The energizing circuit into which condenser Cl discharges can be traced from the right-hand erminal of condenser Cl over front contact 8 of relay WTR, front contact 14 of relay AH when that relay is picked up, top winding 15 of relay AH in multiple with resistor R3 and winding l6 of relay B1) to wire l7 and thence to the lefthand terminal of condenser CI. The energizing circuit into which condenser C2 is discharged can be traced from the right-hand terminal of condenser C2 over back contact ll of relay WTR, three multiple paths to wire H and thence to the left-hand terminal of condenser C2, the first path including lower winding iii of relay AH, the second path including resistor RI and winding 19 of relay BH and the third path including resistor R2 and winding 2| of relay AD.

A slow release relay ABD is preferably associated with the slow pick-up relays AD and BD by being controlled by a circuit extending from terminal 13 of the current source over either front contact 22 of relay AD or front contact 23 of relay BD, winding 26 of relay ABD, wire I! and to terminal C of the current source. Relay ABD is provided to avoid possible signal flashing of the wayside signal whose operating circuits are governed by the group of slow pick-up relays as will later appear, and relay ABD may not be needed.

Relay AH and the associated series of slow pick-up relays selectively control the operating circuits of a wayside signal WS which governs trafiic through section W-X. Signal WS may be any standard type of wayside signal and as here shown it comprises two searchlight signal mechanisms SI and S2 mounted on a single mast. In accordance with the well-known construction for searchlight signals, each mechanism SI and S2 includes a rotor 12 and a field winding I3 for operating three color screens G, R and Y in front of an illuminated lamp 25, the particular color screen positioned in front of the lamp being in accordance with the polarity of the energization of field winding I3. When field winding [3 of a signal mechanism is deenergized, the rotor l2 of that mechanism is biased to a position where the red color screen R is moved in front of the lamp and a red light is displayed, when field winding I3 is energized by current of reverse polarity, the rotor I2 is operated to move the yellow color screen Y in front of the lamp and a yellow light is displayed and when winding I3 is energized by current of normal polarity, rotor I 2 is operated to move the green color screen G in front of the lamp and a green light is displayed. As indicated diagrammatically, the rotor 12 of each signal mechanism operates circuit controlling contacts in the usual manner for such searchlight signals.

A code transmitter CT is also included in the apparatus. Code transmitter CT is preferably of the well-known motor driven type which is provided with two contact members 26 and 21 each of which contact members is operated in a cyclic manner as long as current is supplied to the motor element of the code transmitter. In the form of the invention disclosed in Fig. 1, code transmitter CT is arranged so that in the cyclic operation of contact member 25 it is up to engage a contact 28 for .1 second and is down to engage a contact 29 for .3 second. In the cyclic operation of contact member 21 it is up to engage a contact 30 for .1 second and is down to engage a contact 3| for .9 second each cycle.

The code transmitter CT controls the operating circuits for relay WR associated with the section next in the rear, each such circuit being also controlled by relay AH, the series of slow pick-up relays and the contacts operated by the signal mechanisms Si and S2.

Since relay XR is controlled in a manner similar to relay WR, it follows that relay XR is controlled by the code transmitter and the decoding relays governed by the track circuit for the section next in advance.

It is believed that the operating circuits for signal WS as well as the circuit for controlling relays WR and KR. can best be understood from a description of the operation of the apparatus.

' In describing the operation of the apparatus of Fig. l, I shall first assume a train occupies section WX shunting the track circuit and causing track relay WTR. to be inactive with its back contacts l6 and I! closed. Under this traffic condition relay AH and all of the slow pick-up relays BI-I, AD and DB are released because they are energized only by current supplied from condensers Cl and 02. It is to be noted, however, that condenser CI is now connected across the current source and is fully charged. Relay ABD is also deenergized and released because both relays AD and BD are released. The operating circuits for winding l3 of the mechanisms SI and S2 are now all open and each mechanism is biased with its respective color screen R in front of the lamp so that the signal WS displays a red light over a red light to give a stop signal indication. Relay WR is provided with a circuit comprising terminal 13, contact 32-33 and contact 34-35 of mechanism SI both closed when the winding I3 of that mechanism is deenergized, wire 36, contact 26-29 of code transmitter CT, wire 31, contact 38-39 and contact 4II-4I of mechanism S2 both closed when its winding I3 is deenergized, wire 42, winding of relay WR and terminal C. Since contact 26-29 of the code transmitter CT is open .1 second and closed .3 second each operation cycle of contact member 26, the relay WR is released .1 second and picked up .3 second each such operation cycle so that the approach code of Fig. 3 is impressed upon the track circuit current for the section next in the rear as long as the train occupies section WX.

I shall next assume the train in section W-X advances to the right and occupies the section next in advance of section WX. Relay XR which is controlled by the track circuit apparatus for the section next in advance in the same manner relay WR is controlled by the track circuit apparatus of section WX is now operated to impress the approach code upon the current of the track circuit of section W-X and code following track relay WTR is correspondingly operated. The first time relay WTR is picked up, the energy stored in condenser CI discharges into an open circuit because front contact I4 of relay AH is now open and hence the energy stored in condenser CI performs no useful function during this first on period of the code. Condenser C2 is charged during this first on period due to the closing of front contact 9 of relay WTR. When relay WTR is released during the first .1 second off period, condenser CI is recharged and condenser C2 discharges into its associated energizing circuit and relay AH is picked up due to the energization of its lower winding I8. Neither slow pick-up relay BH nor AD, however, is picked up by the discharge from condenser C2 because the duration of the off period is only .1 second whereas the pick-up periods for relays BH and AD are .3 and .9 second, respectively. On the next on period of the code and relay WTR is picked up, condenser CI discharges into its associated energizing circuit and relay AH is retained picked up due to the energization of its top winding I5. Relay ED is not picked up by the discharge of condenser CI, however, because the duration of the on period is only .3 second whereas the pickup period of relay ED is .9 second. Consequently, relay AH is retained energized due to the alternate energization of its two windings as long as relay WTR is operated in step with the approach code. and relay ABD, however, are all deenergized. With only relay AH picked up, the winding I3 of mechanism SI is energized at reverse polarity by current flowing from terminal B over front contact 43 of relay AH, back contact 44 of relay ABD, winding I3 of mechanism SI, back contact 45 of relay ABD, wire I! and to terminal C; and mechanism SI is operated to move its color screen Y before the lamp. Mechanism S2 remains deenergized displaying a red light and hence signal WS now displays a yellow light over a red light to give an approach signal indication. The relay WR is now provided with a circuit comprising terminal B, contact 32-46 of mechanism SI closed when that mechanism is operated to display a yellow light, front contact 41 of relay AH, contact 26-28 of code transmitter CT, wire 31, contact 38-39 and contact 40-4I of mechanism S2, wire 42, winding of relay WR and terminal C. Since contact 26-28 of the code transmitter The series of slow pick-up relays is closed for .1 second and open for .3 second each operation cycle of contact member 26, relay WR is operated accordingly to impress the approachslow code of Fig. 3 on the current of the track circuit for the section next in the rear when section W-X is unoccupied and the section next in advance of section W-X is occupied.

I shall next assume that the train moves to the right out of the section next in advance and cocupies the second section in advance of section W-X. Since relay XR is controlled in the same manner as relay WR, relay XR is now controlled to impress the approach-slow code upon the current of the track circuit for section W-X and relay WTR is correspondingly operated. When relay WTR is released during the off period of the approach-slow code, condenser C2 discharges to energize winding I8 of relay AH and to energize winding I9 of relay BH to pick up that relay because the duration of the 01f period is .3 second which is the same as the pick-up period of relay BH. Relay AD whose pick-up period is .9 second is not energized for a period sufficient to be picked up and remains released. During the .1 second on period of the code condenser CI discharges to energize winding I5 of relay AH retaining that relay picked up. Relay BD whose pick-up period is .9 second remains released during this short .1 second on period of the approach-slow code. With relays AH and BH both picked up closing front contacts 43 and 48, respectively, the winding I3 of each mechanism SI and S2 is energized at reverse polarity to cause each mechanism to operate its color screen Y before the respective lamp so that signal WS displays a yellow light over a yellow light to give an approach-slow signal indication. The circuit for winding I3 of mechanism SI is the same as traced hereinbefore, while the circuit for winding I3 of mechanism S2 extends from terminal B over front contacts 43 and 48 of relays AH and BH, respectively, back contact 49 of relay BD, winding I3 of mechanism S2, back contact 50 of relay BD and to terminal C. Relay WR is now provided with a circuit comprising terminal B, contact 32-46 of mechanism SI, front contact 4'! of relay AH, contact 21-30 of code transmitter CT, front contact 5| of relay BH, contact 40-52 of mechanism S2 closed when that mechanism displays a yellow light, wire 42, winding of relay WR and terminal C. Since contact 21-30 of the code transmitter is closed .1 second and open .9 second each operation cycle of contact member 27, the relay WR is operated accordingly to impress the approach-medium code of Fig. 3 upon the current of the associated track circuit when two sections in advance of the associated section are unoccupied and the third section in advance is occupied.

Assuming next that the train advances to the right another track section so that there are two unoccupied sections between section WX and the section occupied by the train, the relay XR is operated to impress the approach-medium code on the track circuit current for section WX. During the off period of this code, condenser C2 discharges into the associated energizing circuit and relays AH, BH and AD are all picked up because the duration of the 01f period of the code is .9 second. During the .1 second on period of this code, condenser CI discharges into its associated energizing circuit and retains relay AH picked up, but relay BD remains released. With relay AD picked up closing front contact 22, relay ABD is picked up closing its front contacts 53 and 54 to pole change the circuit for winding I 3 of mechanism .SI so that mechanism SI is energized at normal polarity to move the color screen G in front of the lamp. The winding I3 of mechanism S2 is energized at reverse polarity over a circuit the same as previously described except front contact 57 of relay ABD is in multiple with front contact 48 of relay BH. Consequently,

signal WS now displays a green light over a yellow light to give an approach-medium signal indication. Relay WR is now provided with a circuit comprising terminal B, contacts 3233 and 34-26 closed when the mechanism SI is operated to display a green light, front contact I2 of relay ABD, contact 2'l3l of code transmitter CT, front contact 5! of relay EH, contact it-52 of mechanism S2, wire 52, winding of relay WR and terminal G. Since contact 2?3I of code transmitter CT is closed .9 second and open .1 second each operation cycle oi contact member 21, relay WR is correspondingly operated to impress the clear code of Fig. 3 upon the current of t -e associated track circuit when there are three unoccupied sections in advance of the associated track section. 7

Assuming the train moves another section to the right so that there are three unoccupied sections between the section occupied by the train and section WX, the relay XR which is operated similar to relay WR is now operated to period of this code, condenser C2 discharges into the associated energizing circuit for .l second and relay AH is retained energized, but neither relay BH nor AD is energized for a suificient period to I on period is-.9 second which is the same as the pick-up period of relay BD. Relay ABD is now picked up over front contact 23 of relay BD. Under this combination of the relays, winding I3 of mechanism S! is energized at normal polarity the same as before. When relay ED is picked up closing front contacts and 56, the circuit for winding 13 of mechanism S2 is pole changed and that winding is energized at normal polarity. Since both signal mechanisms S5 and S2 are now energized at normal polarity, signal WS displays a green light over a green light to give a clear signal indication. Relay WR is provided with a circuit comprising terminal B, contacts 3233 and 3 l2 3 of mechanism SI, front contact I2 of relay ABD, con act ET-SI of code transmitter CT, front contact 58 of relay BD, contacts 38-459 and itii of mechanism S2, wire :32, winding of relay WR and terminal C. Consequently, relay WR is still operated to impress the clear code upon the current of the associated track circuit.

Among the advantages of the apparatus of Fig. l is the assurance of operation of the code following track relay since energy used for energizing the decoding relays is obtained by the storage of energy in either the condenser CI or C2 over contacts of the code following relay closed during a selected one of the on and off periods of the code, and the discharge of such stored energy to the decoding relays over contacts of the code the code. When condensersCI and C2 are of t-he electrolytic type, the negative temperature coefficient of such condensers will automatically compensate for the increase in the resistance of the windings of the slow pick-up relays caused.

bysuch increase in temperature. Thus a substantially uniform pick-up period for each decoding relay irrespective of changes in temperature In the form of the invention disclosed in Fig. 2,

the apparatus is similar to that of Fig. 1 and the apparatus of Fig. 2 will be described only in the manner whereinit difiers from the apparatus of Fig. 1. The track circuitfor section WX of Fig. 2 is provided with a code following track relay WTRI- which differs from track relay WTR of Fig. 1 in that relay WTRI isprovided with two setsfof the well-known continuity transfer type of contact. The preselected cyclic patterns for the different codes for the apparatus of Fig. 2 differ from the cyclic patterns used with the apparatus of Fig. 1 both in the relative and absolute durations of the on and off periods. The cyclic patterns for the. different codes'used with the apparatus of Fig. 2 will be apparent from an inspection of Fig. 4 when considered with the explanation of the cyclic patterns illustrated for the codes in Fig. 3. The reactance devices of Fig. 2 are indicated at MI and M2 and each device includes a winding mounted on a magnetic I core, the device MI including a winding BI and the device M2 including a winding BI. When relay W'I'RI is released closing back contact 62-63, winding 6d of device-MI is connected with the B and C terminals of the current source and current flows in winding 69 to store energy in the magnetic core of device MI. When relay WTRI is picked up closing front contact 63-454, the winding 6% of device MI is disconnected from the current source and is connected to an energizing circuit to be later referred to and the magnetic energy stored in the magnetic core of device MI decays to induce an electromotive force in winding 6! which causes current to flow in such energizing circuit. In like manner when relay WTRI is picked up closing front contact 65-65,'the winding [SI of device M2 is connected with the B and C terminals of the current source and current flows in winding BI causing magnetic energy to be stored in the magnetic core of device M2, and when relay WTRI is released closing back contact 655 I, winding tI. is disconnected from the current source and connected to an energizing circuit to be shortly described and current flows in such circuit due to the dying away of the magnetic energy.

The energizing circuits associated with windings 6i) and SI of devices MI and M2 control the check relay AH and the series of slow pick-up relays BH, AD and BD all of which relays are similar to those of Fig. 1. To be explicit the energizing circuit supplied with current from reactance device MI can be traced from the lefthand terminal of winding t0 over wire I'I, winding I5 of relay AH in multiple with resistor R6 and winding I6 of relay BD, front contact I4 of following relay closed during the other period of relay AH when closed, an asymmetric unit 68 preferably of the copper oxide rectifier type, front contact 6364 of relay WTRI and to the righthand terminal of winding 60. The energizing circuit supplied with current from reactance device MZ can be traced from the left-hand terminal of winding 6| over wire i1, three multiple paths one including winding E8 of relay AH, a second one including resistor R4, winding 19 of relay BH and front. contact I of relay AH, and the third path including resistor R5, winding 2| of relay AD, front contact ll of relay BH and front contact 10 of relay AH, and then through an asymmetric unit 69 also preferably of the copper oxide rectifier type, back contact 66-61 of relay WTRI and to the right-hand terminal of winding 6|. It should be observed that the path including winding 2! of relay AD is completed over front contact H of the relay BH and the front contact 10 of relay AH and the path including winding I9 of relay BH includes the front contact 10 of relay AH.

To agree with the cyclic pattern illustrated in Fig. 4, resistor R4 is proportioned to give relay BH a .2 second pick-up period and resistors R and R6 are proportioned to give slow pick-up periods of 1.2 secondsfor relays AD and BD, respectively.

In Fig. 2, the operating circuits for signal mechanisms SI and S2 of wayside signal WS and the circuits for controlling relay WE are substantially the same as in Fig. l.

The operation of the apparatus of Fig. 2 will be apparent from an inspection of Fig. 2 when considered with the description of the operation of the apparatus of Fig. 1 and it is suflicient to describe the operation of theapparatus of Fig. 2 only briefly to point out the results accomplished under the several different trafiic conditions. When a train occupies section WX and track 'relay WTRI is inactive, relay AH and the series of associated slow pick-up relays are all released so that the winding 13 of each signal mechanism SI and S2 is deenergized and the signal WS displays a stop signal indication. Relay WR associated with the track circuit for the section next in the rear is provided with a circuit including terminal B, contacts 32'33 and 34-35 of mechanism SI, contact 25-29 of code transmitter CT, contacts 3839 and 4B4l of mechanism S2, winding of relay WR and terminal C, and consequently relay WR is operated to impress the approach code of Fig. 4 upon the track circuit current of the associated section as long as section W- X is occupied because contact 2629 is closed .2 second and is open .1 second each code cycle of contact member 26 of the code transmitter.

When the train moves from section W-X of Fig. 2 to the right to clear that section and occupy the section next in advance, relay XR is operated to effect the approach code upon the current of the track circuit of section WX and track relay WTRI is correspondingly operated. The first time relay WTRI is picked up, the energy stored in device MI effects no useful purpose because the associated energizing circuit is open at front contact I4 of relay AH, but energy is stored in device M2. On the first off period of the code and relay WTR! is released, energy is again stored in device MI and the energy stored indevice M2 is applied to its associated energizing circuit and relay AH is picked up, but neither relay BH nor AD is picked up because the duration of the off power is only .1 second whereas the pick-up periods for the relays AD and BH are .2 second and 1.2 seconds, respectively.

On the next on period of the code, the winding l5 of relay AH is energized to retain that relay picked up due to the current created by the dying away of the magnetic energy stored in device Ml, but relay ED is not picked up because the duration of the on period is .2 second whereas the pick-up period of relay ED is 1.2 seconds. It follows that relay AH is retained picked up by the alternate energizing of its windings as long as relay WTRI is operated at the approach code. With relay AH picked up closing front contact 43, the winding l3 of mechanism SI is energized at reverse polarity and mechanism S2 is deenergized and signal WS displays an approach signal indication. Relay WR is now controlled over a circuit which includes terminal B, contact 32-46 of mechanism SI, front contact 31 of relay AH, contact 26-28 of code transmitter CT and then as previously traced. Hence relay WR is operated to impress the approach-slow code of Fig. 4 on the track circuit of the associated section when the section next in advance is unoccupied and the second section is occupied, because contact 26-28 is closed .1 second and is open .2 second each operating cycle of contact member 26.

When the train advances another section to the right so that there is one unoccupied section between section WX and the section occupied by the train, relay XR is operated to impress the approach-slow code on the track circuit current of section WX and code following relay W'TRI is correspondingly operated. Relays AH and BH are now picked up, relay AH being picked up due to the alternate energization of its two windings and relay BH being picked up because the duration of the off period of the code is .2 second and the current created by reactance device M2 continues to flow in the winding of relay IBH for the full pick-up period of that relay. With relays AH and BH picked up closing front contacts 43 and 48, the winding I 3 of each mechanism SI and S2 is energized at reverse polarity and signal WS displays an approach-slow signal indication. Relay WR is now provided with a circuit that comprises terminal B, contact 32-46 of mechanism SI, front contact 41 of relay AH, contact 2130 of code transmitter CT, front contact 5| of relay BH, contact 4ll--52 of mechanism S2 and as previously traced. Hence relay WR is operating to impress the approach-medium code of Fig. 4 on the current of the associated track circuit in response to two sections in advance being unoccupied and the third section in advance being occupied.

When the train moves another section to the right and there are two unoccupied sections between section WX and the section occupied by the train and relay XR is operating to impress the approach-medium code on the current of the track circuit of section WX, relays AH, BH and AD are all picked up. Relay A-H is picked up as before and both relays BH and AD are picked up because the duration of the off period is 1.2 seconds. Relay ABD is now picked up over front contact 22 of relay AD and pole changes the circuit for winding is of mechanism SI so that signal WS now displays an approach-medium signal indication. The circuit for relay WR comprises terminal B, contacts 3233 and lid-20 of mechanism Si, front contact 12 of relay ABD, contact 2l3l of code transmitter CT and as previously traced, and relay WR is operated to impress the clear code on the current of the associated track circuit in response to three sections in advance being unoccupied.

With the train moving another section to the right so that there are three unoccupied sections between section WX and the section occupied by the train and relay XR. is operated to impress the clear code on the current of track section WX, relays AH and BD are picked up. Relay AH is picked up as previously described and relay ED is picked up due to the 1.2 seconds on period of the code. Relays BH and AD are now released because the .1 second on period of the code is insuflicient to pick up these relays. Relay ABD is now energized over front contact 23 of relay BD, and with relays AH, BD and ABD picked up, the signal WS is operated to display the clear signal indication. The circuit for relay WR now includes terminal B, contacts 32--33 and 342i! of mechanism Si, front contact 72, contact 2'l-3l of code transmitter CT, front contact 58 of relay BD and thence as previously traced and relay WR is still operated to impress the clear code on the current of the associated track circuit.

It is apparent that the apparatus of Fig. 2 possesses the same advantages as the apparatus of Fig. 1. In this connection, it is pointed out that the asymmetric units 68 and 69 are interposed in their respective circuits so as to pass current produced by the energy stored in the associated reactance device and to block the flow of any current in the energizing circuit from the source of direct current. Also when units 58 and 69 are of the copper oxide rectifier type, the decrease in resistance in the forward direction of the unit when the temperature increases automatically acts to compensate for the increase in the resistance of the windings of the associated slow pick-up relays due to such increased temperature. Furthermore, by proper proportioning of devices Ml and M2 so that magnetic saturation is effected, a substantially uniform voltage is applied to the respective energizing circuit notwithstanding variations in the voltageof the charging source.

It is to be observed that apparatus embodying my invention can be applied to track circuits using coded alternating current as well as coded direct current. Also the apparatus can be used with train carried apparatus of a railway cab signal system employing time codes of the type involved.

While the invention has been described in connection with a four-block five-indication wayside signal system, it is apparent that the method of coding and decoding may be applied to apparatus providing a greater or a lesser number of signal indications if desired.

In connection with the codes here used, it is to be observed that the .1 second period of each code is not used to selectively pick up any corresponding decoding relays, but rather is used to energize the check relay AH and keep the energizing circuits for the series of decoding relays active to guarantee the presence of the code. It is further utilized in effecting the most restrictive proceed indication, namely, the approach signal indication. Furthermore, this .1 second period of each code is used as an interval in which to store energy in one or the other of the two reactance devices.

In wayside signal systems for railways, it is necessary to at times provide a special control for highway crossing signals. In code systems of the type here involved it has been proposed to provide such special control for highway crossing signals by applying at times to the control track circuit for such highway crossing signals noncoded or steady energy. Such non-coded energy picks up the code following track relay and retains it steadily picked up to stop the warning operation of the highway crossing signal, but the code following track relay when steadily picked up still causes the wayside railway signal to remain at its stop position. Since in the apparatus embodying my invention as here disclosed operation of the code following track relay is required to retain picked up the check relay and any of the decoding relays, and since the check relay AH can be picked up at the start of any code only after the code following track relay has first been picked up and then released, it is obvious that steady or non-coded energy can be applied to a track circuit at a highway crossing location to retain the code following track relay steadily picked up to clear out or discontinue the warning operation of the highway crossing signal when the rear of a train passes over the highway and vacates the approach track section to the highway crossing without changing the stop indication of the wayside signal located at the entrance of such track section.

Although I have herein shown and described only two forms of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my inven tion.

Having thus described my invention, what I claim is:

1. In signaling apparatus for use with a signal system having a transmitting circuit supplied with coded energy of anyone of a plurality of diiierent time codes each of which codes consists of a distinctive cyclic pattern which pattern is made up of an on and an off period with the ofi period of each code of a distinctive preselected duration and to which circuit is con nected a code following relay for operation thereof in step with the on and off periods of such time codes, the combination comprising, a reactance device, a circuit including a contact of said code following relay to connect a source of direct current with said reactance device during the on period of each code cycle to store energy in said device, a series of relays, each of which is provided with a distinctive slow pick-up period, and another circuit including a contact of said code following relay to connect said reactance device with said series of relays during the off period of each code cycle to energize said series of relaysby said stored energy to pick up a number of the relays as determined by the duration of the off period of the particular cyclic pattern.

2. In signaling apparatus for use with a signal system having a transmitting circuit supplied with coded energy of any one of a plurality of diiierent times codes each of which codes consists of a distinctive cyclic pattern which pattern is made up of an on and an off period with the off period of each code or" a distinctive preselected duration and to which circuit is connected a code following relay for operation thereof in step with the on and of? periods of such time codes, the combination. comprising, a reactance device, a circuit including a contact of said code following relay to connect a source of direct current with said reactance device during the on period of each code cycle to store energy in said device, a first and a second slow pick-up relay provided with different preselected slow pick up periods, and another circuit including a contact of said code following relay to connect said reactance device to said slow pick-up relays during the off period of each code cycle to energize the slow pick-up relays by said stored energy for selectively picking up such relays according to the duration of the off period of the particular cyclic pattern.

3. In signaling apparatus for use with a signal system having a transmitting circuit supplied with coded energy of any one of a plurality of different time codes each of which codes consists of a distinctive cyclic pattern which pattern is made up of an on and an off period each of a preselected duration and to which circuit is connected a code following relay for operation thereof in step with the on and off periods of such time codes, the combination comprising, a first and a second reactance device each adaptable of storing energy, a first circuit including a contact of said code following relay to connect a source of direct current with said first reactance device during the off period of each code cycle to store energy in said first device, a second circuit including another contact of said code following relay to connect a source of direct current with said second reactance device during the on period of each code cycle to store energy in said second device, a first and a second relay means each operable to difierent positions according to the time interval the respective relay means is energized, a first energizing circuit including a contact of said code following relay to connect said first reactance device with said first relay means during the on period of each code cycle to energize that relay means by the energy stored in said first device for a time interval corresponding to the on period of the particular cyclic pattern, and a second energizing circuit including a contact of said code following relay to connect said second reactance device with said second relay means during the off period of each code cycle to energize that relay means for an interval corresponding to the off period of the particular cyclic pattern.

4. In combination, a code following relay operable between two positions in step with the on and off periods of coded energy of any one of a plurality of different time codes supplied thereto, an energy storing device capable of storing a predetermined amount of energy therein, a first circuit including a contact of said code following relay closed at a selected one of its two positions to connect a source of direct current to said energy storing device, said first circuit proportioned to store energy rapidly and fully charge said energy storing device in the shortest code period used in said different codes, an electromagnetic means capable of operation to different positions according to the duration said means is effectively energized, a second circuit including a contact of said code following relay closed at the other one of its two positions to connect said energy storing device with said electromagnetic means, and said second circuit proportioned to discharge the stored energy at a rate to effectively energize the electromagnetic means for the longest code period used in said different codes.

5. In combination, a code following relay operable between two positions in step with the on and off periodsof coded energy of any one of a plurality of different time codes supplied thereto, a condenser of a predetermined capacity, a first circuit including a contact of said code following relay closed at a selected one of its two positions to connect a source of direct current to said condenser, said first circuit proportioned to fully charge said condenser in the shortest code period used in said different codes, a series of slow pick-up relays which relays are provided with different preselected pick-up periods, and a second circuit including a contact of said code following relay closed at the other one of its two positions to connect said condenser with said series of slow pick-up relays, said second circuit proportioned to discharge said condenser at a rate which effectively energizes each relay of said series of relays for the longest code period used in said different codes to pick up the slow pickup relays according to the particular code operating said code following relay.

6. In combination, a code following relay operable between two positions in step with the on and off periods of coded energy of any one of a plurality of different time codes supplied thereto, an inductor having a winding mounted on a magnetic core, a first circuit including a contact of said code following relay closed at a selected one of its two positions to connect said inductor winding with a source of direct current, said first circuit proportioned to substantially magnetically saturate said inductor core in the shortest code period used in said different codes, a series of slow pick-up relays which relays are provided with different preselected pick-up periods, and a second circuit including a contact of said code following relay closed at the other one of its two positions to connect said inductor winding with said series of slow pick-up relays, said second circuit proportioned to effectively energize each relay of said series of relays for the longest code period used in said different codes by the current created by the decay of the magnetic flux of said inductor core to pick up the slow pick-up relays according to the particular code operating said code following relay.

7. In signaling apparatus for use with a signal system having a transmitting circuit supplied with coded energy of any one of a plurality of difierent time codes each of which codes consists of a distinctive cyclic pattern which pattern is made up of an on and an off period of a preselected duration and to which circuit a code following relay is connected for operation thereof in step with the on and off periods of the particular code supplied, the combination comprising, a first and a second reactance device, a first circuit including a contact of said code following relay to connect a source of direct current to said first reactance device during the off period to store energy in said first device, a second circuit including a contact of said code following relay to connect a source of direct current to said second device during the on period to store energy in said second device, a check relay having two windings, a first and a second decoding relay each of which is provided with a distinctive slow pick-up period, a third circuit including a contact of the code following relay closed during the ofi period to connect said second reactance device to one winding of the check relay and to said first decoding relay to pick up by the energy stored in the second device the check relay and also the first decoding relay when the duration of the off period is at least equal to the slow pick-up period of the first decoding relay, and a fourth circuit including a contact of the code following relay closed during the on period and a front contact of the check relay to connect said first reactance device to the other winding of the check relay and to said second decoding relay to retain by the energy stored in the first device the check relay picked up and to pick up the second decoding relay when the duration of the on period is at least equal to the slow pick-up period of the second decoding relay.

8. In signaling apparatus for use with a signal system having a transmitting circuit supplied with coded energy of any one of a plurality of different time codes each of which codes consists of a distinctive cyclic pattern which pattern is made up of an on and an off period each of a preselected duration and to which circuit is connected a code following relay for operation thereof in step with the on and off periods, the combination comprising, a first and a second reactance device, a first circuit including a contact of said code following relay to connect a source of direct current to said first reactance device during the off period to store energy in said first device, a second circuit including another contact of said code following relay to connect a source of direct current to said second reactance device during the on period to store energy in said second device, a check relay having two windings, a series of decoding relays each of which relays is provided with a slow pick-up period preselected to agree with either the on or off period of a particular code, a third cir-' cuit including a contact of said code following relay closed during the oil period to connect said second reactance device to one winding of the check relay and certain ones of said decoding relays to pick up by the energy stored in the second device the check relay and also such decoding relays Whose slow pick-up periods are not greater than the duration of the ofi period, and a fourth circuit including a contact of the code following relay closed at the on period and a front contact of the check relay to connect the first reactance device to theother winding of the check relay and to at least one other of the decoding relays to retain by the energy stored in the first device the check relay picked up and to pick up the last mentioned decoding relay when its slow pick-up period is not greater than the duration of the on period.

EARL M. ALLEN.

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