US2124660A

US2124660A - Railway signaling

Info

Publication number: US2124660A
Application number: US26784A
Authority: US
Inventors: James J Vanhorn
Original assignee: Union Switch and Signal Inc
Current assignee: Hitachi Rail STS USA Inc
Priority date: 1935-06-15
Filing date: 1935-06-15
Publication date: 1938-07-26
Anticipated expiration: 1955-07-26

Description

July 26, 1938. J. .LVANHCRN- RAILWAY SIGNALING Original Filed June 15, 1935 5 Sheets-Sheet l H P E ME R Y o E TH N N R w o N w 1 s A m a Y m U B H mwwm ww N l S M July 26, 1938. v J..J. VANHORN RAILWAY SIGNALING Original Filed June 15, 1935 5 Sheets-Sheet 2 .wwwmwmmw Q ESQ Eh Q s \a mg m ww y R Q & A] \H w INVENTOR James HIS ATTORNEY July 26, 1938. J. J. VANHORN RAILWAY SIGNALING Original Filed June 15, 1935 5 Sheets-Sheet 3 N E L m. a NW Aw Bm m S m6 INVENTO'R q-Ja122asJ born H I s ATTORNEY July 26, 1938. J. J. VANHORN RAILWAY SIGNALING 5 Sheets-Sheei 4 Original Filed June 15, 1935 NTOR July 26, 1938. J. J. VANHORN RAILJWAY SIGNALING Original Filed June 15, 1935 S'Sheets-Sheet 5 All. H

INVENTOR J. Kmlzozn.

James k w m b w M \vqw. .0 ({IL 1 HIS ATTORNEY Patented July 26, 1938 PATENT OFFICE RAILWAY SIGNALING James J. Vanhorn, Swissvale, Pa., assignor to The Union Switch & Signal Company, Swissvale, Pa., a. corporation of Pennsylvania Application June 15, 1935, Serial No. 26,784 Renewed October 30, 1936 30 Claims.

My invention relates to railway signaling, and particularly to signaling involving wayside signals located along a trackway for governing the passage of trains.

A feature of my invention is the provision of novel and improved apparatus for establishing -a distinctive control for each of four track sections in the rear of an occupied section without the use of line control wires. Each distinctive control is effective to cause a corresponding aspect of the waysidesignals, whereby there is produced a four block, five indication system of signaling. A further feature of my invention is the provision of apparatus, utilizing a direct current and an alternating current source of power, for controlling wayside signals in such a manner that trains are kept moving by signal indication in the event of failure of the alternating current source of power. Other features and advantages of my invention will appear as the specification progresses.

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

In the accompanying drawings, Figs. 1A, 1B and 1C are diagrammatic views which, when placed end to end in the order named, illustrate one form of apparatus embodying my invention. Fig. 2 is a diagrammatic view illustrating a modification of a portion of the apparatus'shown in Figs. 1A, 1B and 10. Figs. 3A, 3B and 3C are diagrammatic views which, when placed end to end in the order named, illustrate another form of apparatus embodying my invention.

Similar reference characters refer to similar parts in each of the several views.

Referring first to Figs. 1A, 1B and 10, the

reference characters

2 and 2A designate the track rails of a stretch of railway track along which trafiic normally moves in the direction indicated by the arrows. These rails are dividedby the usual insulated joints 3 into a plurality of track sections V-W, WX, X-Y, YZ, etc.

Each track section is provided with a direct current track circuit which includes the track rails in series, a track battery 5 connected across the rails at one end of the section in series with a limiting resistor 6, and a polarized direct current track relay R (with a suffix corresponding to the location) connected across the rails at the other end of the section. The winding of each track relay R is connected directly with the track rails as will be readily understood by an inspection of Figs. 1A, 1B and 1C. The trackbattery 5 for each section is reversibly connected with the track rails by pole-changing contacts of the direct current track relay R for thenext section in advance. For example, when the track relay RW is energized the track battery 50f the section V-W is connected with the

track rails

2 and 2A over the front points of the neutral contacts I and I I of the track relay RW to supply current of one polarity, and which polarity I shall refer to in the following description as being of normal polarity. At such time as the track relay RW is deenergized, the connection of the battery with the track rails is reversed at the back points of contacts l0 and l l to supply current of the opposite polarity, and which polarity I shall refer to as being of reverse polarity. The track relay RV for the section VW, when energized with current of normal polarity, will shift its polar contacts l2 and 13 into engagement with their respective lefthand contacts, that is, to the position shown in Fig. 1A. When the relay RV is energized with current of reverse polarity, the polar contacts I2 and I3 will be shifted to their right-hand positions, that is, to the positions opposite that shown in Fig. 1A. Each of the remaining track batteries of my system is connected with the rails of the associated section in the same manner as battery 5 of section VW, and each of the remaining .direct current track relays responds to the polarity of the direct current supplied to the associated track section in the same manner as the track relay RV.

It will be noted that the relay contacts are not in all instances directly under the relay actuating such contacts. Each such contact, however, is provided with the same reference character as that applied to the actuating relay.

Each track section is also provided with an alternating current track circuit which comprises the track rails in series and which includes a secondary M of a track transformer, designated by the reference character F with a suitable sufiix, connected across the rails'at one end of the sec- 7 tion and a polarized alternatingcurrent track relay, designated by the reference character A with a suitable sufiix, receiving energy from the rails at the other end of the section. An impedance 1 for regulating the flow of alternating current in the track circuit is connected in series with the secondary l4. The track winding of each relay A is connected, in series with a condenser 8, directly across the rails of the associated section. The condenser 8 prevents the flow of direct current in the alternating current relay A, and the high impedance of the direct current relay R prevents the flow of alternating current in that relay. The relays R and A, therefore, although connected to the'same rails, respond only to direct and alternating current, respectively. Each alternating current track relay Ais provided with a local winding 9 which is connected to a suitable source of alternating current, the terminals of which are designated by the reference characters BX and CX.

Associated with each alternating current track relay is a relay having aslow release characteristic and designated by the reference character E with a distinguishing sumx. The relays E, as will be explained more in detail hereinafter, are provided to prevent certain undesirable flashing and tumbling-down of the signals during the time the polar contacts of the alternating current track relays are moving between their normal and reverse positions. I

The primary I5 of the transformerF for each section is connected to terminals BX and CK of the source of alternating current by pole-changing contacts-of the relay-E associated with the section next in advance, provided that the direct current track relay R for such next section in advancevis energized by current of normal p0 larity. For example, the primary l5 of the transformer of the section VW is normally connected with terminals BX and 0X by a circuit which includes normal polar contact 2| and front neutral contact l6 ofthe'relay RW, and front contacts I! and I8 of the relay EW. That is, when relay RW is energized in its normal position, alternating current ofnormal polarity is supplied to relay AV when EW i's energized and current .of reverse polarity is supplied to relay AV when relay EW isdeenergized. When relay RW is deenergized or energized in its reverse position the supply of alternating current for relay AVis disconnected. When relay AV is energized with current of normal polarity its contacts l9 and Zflwill come into engagement with their respective left-hand contacts, and when energized with current of reverse polarity will come into engagement with their respective right-hand contacts." When relay AV is energized so that either its normal polar contact 9 I 9 or'its reverse polar contact l9l20 becomes closed, the relay EV will be energized and 'whenboth such 'co ntacts are opened the relay 'EV will be deenergized, The relay EV, therefore, will become energized or deenergized to close the front or back points, respectively, of its

contacts

22, 23,24 and 25 in accordance with the corresponding energization or deenergization of the relay AV. H V H 'I he alternating current relays A are of a type in which when the track windings of the relays are deenergized, the movable contacts thereof are moved to their intermediateor open positions, in which they do not engage either of the stationary contacts associated therewith. V

Each of the remaining transformers F of my system is connected with the rails of the .associated section and with the terminalsBX and CX in. a manner similar to transformer FW of the section VW, and each ofv the remaining alternating'current track relays responds to the polarity of the alternating current supplied to the associated section in the same manner as the track relay AV and the relay EV.

. The terminals BX and CX at the various sigfn'al locations throughout the track stretch'and from which alternating current is supplied to the local windings! of the alternating current relays A, and the terminals identified by the same reference characters and from which alternating current is supplied to the transformers F, and thus to the track windings of the relays associated with the adjacent signals in the rear, are supplied with alternating current from a common source so that the instantaneous polarity of the current supplied to the local and track windings of each of the alternating current track relays will be properly synchronized.

To sum up thus far, each track section is provided with two track circuits, a direct current circuit and an alternating current circuit which operate independently of each other. The direct current track circuit is energized at all times, and is supplied with direct current of one p0- larity or the other depending upon whether the direct current track relay for the section next in advance is energized or deenergized. The alternating current track circuit is energized only when the direct current track relay for the section next in advance is energized with current of normal polarity, and is then supplied with alternating current of one polarity or the other depending upon whether the slow releasingrelay repeating the alternating current relay for the section next in advanceis energized or deenergized.

' The track relays R are preferably but not necessarily of the retained-neutral polarized type. v .To govern the passage of trains through the stretch of railway, a wayside signal designated b'y 'the reference character H with an appropriate s'ufiix is located at the entrance of each track section. Each of these signals comprises a top unit T and a lower unit L. These units may take any one of several forms of signal mechanism such: as the semaphore, color light, search light, or position light. 'As here illustrated, each unit isa color light signal capable of displaying a green light G,'a yellow light Y and a red light R.

' The manner in which the lamps of'these signals are controlled will bestbe understood by tracing the circuits and explaining the operation of the apparatus simultaneously. i

A train designated by the reference "character K is shown in the section immediately to the right of location Z. The shunt of the Wheels and axles of train K will deenergize the track relays RZ and AZ in the usual manner. RelayRZ being deenergized, current will flow from the terminal'B of a suitable source of direct current through the back point of contact 21 of relay RZ and lamp R of the top unit T of signal HZ to the terminal C of the same source of direct current; so that the lamp R of that unit will be illuminated. Current will also flow from the terminal B of the direct current source through the back point of contact 28 of relay 'RZ and the lamp R of the lower unit L of signal 'us't p I) The connection for the direct current track circuit of the section YZ next in the rear of the section occupied by the train K will be over the back points of contacts 30 and SI of the direct current track relay RZ, and hence the track relay RY will now be energized with direct current ofreverse polarity to shift its polar contact '36 into engagement with its right-hand fixed contact 31. Since the alternating current track circuit for the section Y--Z is open at the front contact 32 of the track relay RZ, the track relay AY will be deenergized as illustrated in Fig. 13'. Consequently, at the location Y, the track relay RY will be energized in the reverse direction, the track relay AY will be deenergized, and the relay EY will be deenergized.

Therefore, current will flow from the terminal B through front point of contact 33 of track relay RY, back point of contact 34 of relay EY and lamp Y of the top unit T of signal HY to terminal C; so that lamp Y of that unit will be illuminated. Current will also flow from terminal B through front point of contact 35 of relay RY, polar contact 36-3! of relay RY and lamp R of the lower unit L of signal HY to terminal C; so that lamp R of that unit will be illuminated. The aspect of the signal HY, therefore, will be a yellow light above a red light to indicate prepare to stop at next signal.

Considering next the condition of the track circuits for the section X-Y, which is the second section in rear of the section occupied by the train, the direct current track circuit for the section X--Y will be supplied with current of normal polarity because the front points of contacts 40 and ll of relay RY are closed, and the alternating current track circuit for this section will be deenergized because the normal polar contact 42-43 of relay RY is opened. Consequently, the relay RX will be energized with current of normal polarity and the relays AX and EX will both be deenergized.

Current now flows from terminal B of the direct current source at location X through front point of contact 44 of track relay RX, back point of contact &5. of the relay EX, and lamp Y of the top unit T of signal HX to terminal C; so that the lamp Y of that unit will be illuminated. At the same time, current will flow from the terminal B through front point of contact 46 of relay RX, polar contact 41-48 of relay RX, back point of contact is of relay EX and lamp Y of the lower unit of signal HX to terminal C; so that the lamp Y of that unit will be illuminated. The aspect of the signal HX, therefore, will be a yellow light above a yellow light to indicate proceed at not exceeding medium speed. i

I shall next consider the condition of the apparatus for the section W-X, the third section to the rear of the section occupied by the train K. The direct currect track relay RX is energized in the normal direction so that the connection of the track battery 5 at the location X is over the front contacts 58 and 5! of the relay RX, and hence the track relay RW is energized with current of normal polarity to shift its polar contacts to the left-hand position. The track relay RX being energized in the normal direction and the relay EX being deenergized,the alternating current track circuit forthe section W-X is supplied with alternating current of reverse polarity, so that the track relay AW shifts its polar contacts to the right-hand position. Hence, at location W, the track relay RW is energized in the normal direction, the track relay AW is energized in the reverse direction, and the relay EW is energized.

Current will therefore flow from the terminal B of the direct current source at location W through front point of contact 52 of relay RW, front point of contact 53 of relay EW, and lamp G of the top unit T of signal HW to terminal C; so that the lamp G of that unit will be illuminated. Current will also flow from the ter-' minal B of the current source through the front point of contact 54 of relay RW, left-hand polar contact 55-56 of relay RW, front point ofcontact 51 of relay EW, right-hand polar contact 58-59 of relay AW, and lamp Y of the lower unit L of signal I-IW to terminal C; so that the lamp Y of that unit will be illuminated. It follows that the aspect of the signal HW will be a green light above a yellow light to indicate to a train approaching the location approach next signal at not exceeding medium speed.

Considering next the condition of the track circuits for the section V-W, the fourth section to the rear of the section occupied by the train K, the track relay RW is energized in the normal direction so that the connection of the track battery 5 with the track rails of the section VW is over the front points of contacts In and II of the relay RW, and the track relay RV is energized with current of normal polarity. The track relay AW being energized so that the relay EW is energized, the current supplied to the alternating current track circuit for the section V-W is of normal polarity and the track relay AV is energized in its normal position. Hence, at the location V, both the track relays RV and AV are in their normal positions, and the relay EV is energized.

Current therefore flows from the terminal B through the front point of contact 69 of relay RV, front point of contact 23 of relay EV, and

lamp G of the top unit T of signal HV to terminal C; so that lamp G of that unit will be illuminated. Current will also flow from battery terminal B through the front point of contact 6| of relay RV, left-hand polar contact 13-432 of relay RV, front point of contact 22 of relay EV, left-hand contact ZED-453 of relay AV, and lamp G of the lower unit L to battery terminal C; so that the lamp G of that unit will be illuminated. The aspect of the signal HV, therefore, will be a green light above a green light to indicate proceed at normal speed.

From the foregoing description, it is evident that a distinctive control condition is provided for each of the four successive track sections to the rear of an occupied section. These control conditions may be summed up as follows: Both track circuits for the section occupied are shunted in the usual manner to open both the track relays of that section. The first section to the rear of the occupied section has its direct current track circuit supplied with current of reverse polarity and its alternating current track circuit deenergized. The second section has its direct current track circuit supplied with current of normal polarity and its alternating current track circuit deenergized. The third sectionhas'its direct currenttrack circuit supplied with current of normal polarity, and its alternating current track circuit with current of reverse polarity. The fourth section has both its track circuits supplied with current of normal polarity. From these different control conditions, five different signal aspects are obtained, namely, a red light above a red light at the first signal to the rear of a train to indicate stop, a yellow light above a red light at the second signal to the rear of a train to indicate prepare to stop at the next signal, a yellow light above a yellow light at the third signal to the rear of a train toindicate proceed at not exceeding medium speed, a green light above a yellow light at the fourth signal to indicate approach next signal at not exceeding medium speed, and a green light above a green light at the fifth signal to the rear ofa train to indicate proceed at normal speed. I shall term these aspects, stop, approach, medium, approach-medium" and proceed, respectively.

It should be observed that the direct current track relay alone provides the 'first three aspects of the associated signal, and that the alternating to govern movements of trafiic by a three aspect signaling system, providing proach and stop aspects. V

The function of the retained-neutral feature of the direct current track relays and the slow to release feature of the E relays will now be pointed out. The signal HY displays a yellow light above a red light to a train in the section XY as long as the train K occupies the section to the right of location Z. I shall nowassume that while a following train is approachingthe signal HY, the train K moves on out of the section to the right of location Z. Under these conditions, the picking up of the direct current track relay RZ pole changes the direct current track circuit for the section Y-Z, and the track relay RY is deenergized andthen reenergized in its normal direction causing its polar contacts to be shifted from the right-hand position to the left-hand position. The position of the alternating current track relay AY is not changed at this time, and, consequently, the position of the-relay EY is not changed. Shifting the polar contact 36 of the medium, ap

track relay RY shifts the signal control circuitfrom that for the lamp R of the bottom unit L of signal HY to the circuit for the lamp Y of the bottom unit L. The circuit for the lamp Y of the upper unit T is not changed inasmuch as no change takes place in the position of the relays AY and EY. 'It follows that the aspect of the signal HY is changed from that of a yellow light above a red light to that of a yellow light above a The retained-neutral feature of yellow light. the track relay RY prevents the back contact 33 of relay RY from becoming momentarily closed to give a momentary flash of the lamp R of the top unit T. That is, false signal flashing of the signal I-IY is avoided. Furthermore, the retainedneutral feature of relay RY prevents the front contacts 40 and 4| from momentarily opening the circuit for the direct current track relay RX during the pole changing of the'track circuit for section Y-Z. The energization of the direct current track relays for the remaining sections not being disturbed, successive tumble-down of the signal circuits for the sections to the rear of location Y is avoided. r

It has been pointed out hereinbefore that the signal HW displays a: green light above a yellow light during the time the train K occupies the section illustrated in Fig. 1C. Ishall now assume that while a following train is approachingthe signal HW, the train K moves on and vacates the section to the right of location Z. Under these conditions,the'energization of the alternating current track relay AW is changed from'reverse to normal. The direct current track relay RX does not change its position at this time and hence no change takes place in the direct current'track relay RW. The shifting of the polar contactjg of relay AW from its right-hand position to its left-hand position transfers the signal control circuit from that for the lamp Y of the lower unit of signal HW to that for the lamp G. -The slow release feature of the relay EW prevents the back point ofcontact .53 from being momene tarily closedto flash the lamp Y of the top unit T; that is, false signal flashing is avoided. Furs thermore, the front points of contacts I! and [8 of the'relay EW being retained closed, successive tumble-down of the signal circuits to the rear of location W is avoided.

Referring next to Fig. 2, which illustrates'an alternative method for supplying direct and alternating current to the track circuits shown in Figs. 1A, 1B and 1C, I have therein shown the secondary M of the track transformer FZ connected in multiple with the direct current battery rather than in series. vided in series with-secondary M to prevent the flow of direct current in the secondary winding and an impedance 65 is provided in series with the battery 5' to prevent the flow ofalternating current in the battery 5. Otherwise, the apparatus shown in Fig. 2 operates in a manner similar in all respects to' the apparatus embodying my invention shown in Figs. 1A,.1Band 1C. Referring now to Figs. 3A, 3B and 30' which illustrate another form of four block, five indication automatic signaling system displaying the same indications as those described for the system shown in Figs. 1A, 1B and 1C, the principal difference in the apparatus shown in Figs. 3A, 3B and 30 from the apparatus shown in Figs. 1A, 1B and 1C being in the manner in Which the direct current and alternating current energy. is supplied to the rails of a given section. The form of apparatus illustrated in Figs. 1A, 1B and 1C permits direct current energy and alternating current energy tobe supplied simulta'neously'to the rails of a given section, whereas with the form of apparatus shown in Figs. 3A, 3B and 30, either alternating current or direct current, but never both at the same time, is supplied to the rails of a given section.

Associated with each section is a relay having a slow release characteristic and designated by the reference character D-With a distinguishing suffix. The relay D when energized is effective to prevent direct current energy from being supplied to the direct current track circuits for the section next in rear, and when deenergized is effective to A condenser 64 is pro-- prevent alternating current energy from being Y supplied to the alternating current track circuit for such next section in rear. the front point of contact 66 of relay DW of the section W-X is closed, alternating current energy will be supplied to the rails of section V-W, and when the back point of contact 66 is closed direct current energy'vvill be supplied to the rails of section V-W. The relay DW is provided with tWo pick-up circuits. one output terminal of the'rectifier JW through the back point of contact 61 of the direct current track relay RW, front point of contact 68 of the relay EW, and'relay DW to the other output terminal of the rectifier JW. The other circuit passes from one output terminal of the rectifier JW through the front point of contact 6'! of 'the relay RW, normal polar contact 69'l0 of the relay RW, back point of contact 68 of relay EW, and relay DW to the other output terminal of the rectifier JW. The input terminals of the rectifier JW are directly connected to the terminals BX and CK of the alternating current source of For example, when One circuit passes from '18 of relay DZ, the track relay AY will be deenerenergy. The relay DW, therefore, may be energized when the relay RW is released provided the relay EW is energized, or when the relay RW is energized with current of normal polarity provided the relay EW is deenergized. Since the relay EW may be energized only when the alternating current track relay AW is energized, the relay DW will be energized when the track relay AW is energized and the track relay RW is deenergized, or when the track relay AW is deenergized and the track relay RW is energized in its normal position. It is obvious from the foregoing description that either alternating current or direct current but not both simultaneously may be supplied to the section V-W.

Each of the remaining track sections of the modification of my invention illustrated in Figs. 3A, 3B and 3C is provided with a relay W and with a rectifier J, each identified by a distinguishing suffix, and each functioning in the same manner as the relay DW and the rectifier JW.

The alternating current relays A employed in the system shown in Figs. 3A, 3B and 3C of the drawings are of the type which are employed in the system shown in Figs. 1A, 1B and 1C, and have local windings and track windings. The 10- cal windings are energized from a source at the signal location, while the track windings are supplied with current from the track rails. The terminals BX and CX at the various signal locations from which alternating current is supplied to the local windings of the alternating current track relays and to the track transformers, and thereby to the track rails and to the track windings of the alternating current track relays, are all supplied with alternating current from a common source so that the instantaneous polarity of the current supplied to the local and track windings of the track relays will be properly synchronized.

The manner in which the lamps of the signals illustrated in Figs. 3A, 3B and 3C are controlled will best be understood by tracing the circuits and explaining the operation of the apparatus simultaneously.

The train K is shown in the section immediately to the right of location Z. The shunt of the wheels and axles of the train K will release the track relays R2 and AZ in the usual manner.

Both track relays R2 and AZ being deenergized, current will flow from the terminal B of the direct current source of energy through the back point of contact H of relay RZ, back point of contact 18 of relay EZ and lamp R of the top unit T of signal HZ to the terminal C; so that the lamp R of that unit Will be illuminated. Current will also flow from the terminal B through the back point of contact 12 of relay RZ, back point of contact 13 of relay EZ and the lamp R of the lower unit L of signal HZ to the terminal C; so that the lamp R of that unit will be illuminated. The aspect of signal HZ, therefore, will be a red light above a red light to indicate stop The connection for the direct current track circuit of the section YZ next in rear of the section occupied by the train K will be over a circuit including the back points of

contacts

14 and 15 of the track relay RZ and back point of contact 15 of relay DZ so that track relay RY will be energized with direct current of reverse polarity to shift its polar contacts into engagement with its right-hand fixed contacts. Since the alternating current track circuit for the sec-- tion YZ is open at the front point of contact gized so that relay EY will also be deenergized. The relay DY will be deenergized because polar contact B5-86 of track relay RY is opened.

Current will therefore flow from the terminal B through front point of contact 11 of track relay RY, and lamp Y of the top unit T of signal HY to terminal C; so that lamp Y of that unit will be illuminated. Current will also flow from terminal B over front point of contact l9 of track relay RY, polar contact 8!l8 l of relay RY and lamp R of the bottom. unit L of signal HY to: terminal C; so that lamp R of that unit will be illuminated. Thus, the aspect of signal HY will be a yellow light above a red light to indicate prepare to stop at next signal.

Considering next the condition of the apparatus for the section. X-Y, which is the second section in the rear of the section occupied by the train K, the direct current track circuit for section X-Y will be supplied with current of normal polarity because the front points of contacts 82 and 83 of relay RY and the back point of contact 84 of relay DY will all be closed, and the alternating current track circuit for this section will be deenergized because the front point of contact 84 of relay DY is opened. Consequently, the direct current track relay RX will be energized with current of normal polarity and the relays AX and EX will both be deenergized. Therefore, with the train occupying the section immediately to the right of signal HZ, the direct current track relay RX will be energized by current of normal polarity and alternating current track relay AX will be deenergized so that relay EX will also be deenergized. The relay DX will be energized over its control circuit including front point of contact 81 of track relay RX, polar contact 8889 of relay RX and back point of contact 90 of relay EX.

Current now flows from terminal B at location X through front point of contact SI of track relay RX, and lamp Y of the top unit T of signal HX to terminal C; so that the lamp Y of that unit will be illuminated. At the same time current will flow from terminal B through front point of contact 93 of track relay RX, polar contact 9495 of relay RX and lamp Y of the lower unit L of signal I-IX; so that the lamp Y of that unit will be illuminated. The aspect of signal HX, therefore, will be a yellow light above a yellow light to indicate proceed as not exceeding medium speed.

I shall next consider the condition of the apparatus for the section WX, the third section to the rear of the section occupied by the train K. The relay DX being energized, the direct current track circuit for the section W--X will be deenergized so that the direct current track relay RW will be released. The relay EX being deenergized and the relay DX being energized, the alternating current track circuit will be supplied with current of reverse polarity over the back points of contacts. 96 and 9'! of relay EX and the front point of contact 98 of relay DX so that the alternating current track relay AW will be energized by current of reverse polarity. Thus the relay EW will be energized because polar contact 9l00 of alternating current track relay AW will be closed and relay DW will be energized because its other control circuit including back point of contact bl of relay RW and front point of contact 68 of relay EW will be closed.

Current will therefore flow from terminal B at location W, through back point of contact ill! of direct current track relay RW, front point of con- 6 tact I 02 of relay uwand the lamp G of the top unit of signal HW to terminal C. Current will also fiow fromtermi'nal B throughback point of contact 10.3 of track' relay RW, front point of contact I04 of relay EW, reverse polar contact [05 -106 of alternating current trackrelay AW andlamp Y of the lower unit L of signal HW to terminal C. The aspect of signal HW, therefore, will be a green light above a yellow light to indicate approach next signal at not exceeding medium speed. Y 7

Considering next the condition of theapparatus for the section V'W, the fourth section in rear of the section occupied by the train K, the direct current track circuit will be deenergized because the back point of contact 66 of relay DW is opened, and the alternating current track circuit for the section VW will be energized with alternating current of normal polarity over the front points of contacts l 01 and lOB of relayEW because the front point of contact 66 of relay DW is closed. Therefore, the direct current track relay RV Willbe deenergized and the alternating current track relay AV will be energized by current of normal'polarity. The relay EV will be energized because polar contact IMF-H0 of track 7 relay AV is closed and relay DV'will be energized by a circuit including back pointof contact Ill oftrack relay RV and front point of contact I I2 of relay EV. i

Current will therefore flow from terminal B at location V through baclipoint of contact H3 of track relay RV, front point of contact I I4 of relay EV'and lamp'G of the top unit T of signal HV to terminal'C. Current will also flow from terminal B through back'point of contact H5 of track relay RV, front point of contact H6 of relay EV, normal polar contact Ill- L18 oftrack relay AV and lamp G of the lower unit of signal HV to terminal C. The aspect of signal HV, therefore, will be a green. light'above a green light to indicate fproceedat normal speedf It'will be noted that when the alternating current track relay is released the direct current track'relay provides three aspects, namely: me-

dium, approach and"stop, and that when the direct currenttrackrelay isreleasedlthealternating current track relay provides the other two aspects, namelyr approach-medium and clear. Thus the system embodying my invention as illustrated in Figs. 3A, 3B and 30 functions in a manner similar to the system shown in Figs. 1A, "1B and'lC when the alternating current is absent. r

Due to the retained neutral characteristics of the direct current track relays, and the slow'to release characteristic of the relays 'D and E, it

"will be apparent that the system illustrated in Figs; 3A, 3B and 3C is free from undesirable signal flashing and tumble-down of signals previously pointed out for the system illustrated in Figs. 1A,

' 1B and 1C.

From the foregoing description it is apparent that each of the modifications embodying myinvention provides a four-block, five indication signaling system which requires no line control wires,

which is free from undesirable signal flashing.

and tumble-down of signal controlyand which will function to keep tramc moving ,by signal indications even if the alternating current energy is absent.

Although I have herein shown and described only 'a few forms of apparatus embodying my invention, it is understood that various changes and modifications may be made" therein within thescopelo'f the appended'claims' without depart ing from the spirit and scope of my'inventi'on.

Having thus described my invention, what I claim is:

1.- A railway signal system comprising a stretch of railway track divided into sections, a direct current polarized track relay and an alternating current polarized track relay for each section each receiving current from the rails of the section, said direct current relays 'each effective to prevent the flow of alternating current therein and said alternating current relays each con-' nected to the rails of'the associated section by controlled jointly by said direct current and said alternating current'track relays.

2. A railway trafiic controlling system comprising a stretch of railway track divided into sections, adirect current polarized track relay and.

an alternating current polarized track relay for each section each receiving energy from the rails of the section, said direct current relays each efiective to prevent the flow of alternating current therein and said alternating current relays each connected to the rails ofthe associated sec tion by means effective to prevent the flow of direct current'therein, means controlled by the track relays of each sectionforreversibly governing the supply of currents to the rails for the section next in the rear, and trafiic governing means for each sectioncontrolled jointly bysaid direct current track relay and said" alternating rails of thesection, a relay controlled jointly by said direct current andsaid alternating current track relays of each section for governing the supply of currents to the rails of. the section next in'the rear, and signaling means for said stretch controlled jointly by said direct current and said alternating current relays.

4; A railway signal system comprising a stretch of railway track divided into sections, two track relays for each section one direct current track .relay and one alternatingcurrent track relay and each receiving energy from the rails of the section, said direct current relays each effective to prevent the flow of alternating current'therein and said alternating current relays .each connected to the rails of the associated section by means effective to prevent the flow of direct cur- ;rent therein, two sources of current one direct current and one alternating current, means for supplying the rails of each section with direct current or with alternating current but not both simultaneously, and signaling means for said sources of current for each section one direct current and one alternating current, means including a relay governed by the direct current track relay and the alternating current track relay of each section for supplying direct current of one polarity or another or alternating current of one polarity or the other but not both simultaneously to the rails of the section next in rear, and signaling means for said stretch controlled by said track relays.

6. A railway signal system comprising a plurality of successive sections of railway track, two electroresponsive means for each section one direct current and one alternating current and each selectively responsive to the polarity of the current supplied thereto, said direct current electroresponsive means each efiective to prevent the flow of alternating current therein and said alternating current electroresponsive means each effective to prevent the flow of direct current therein, two track circuits for each section one direct current for controlling the direct current electroresponsive means and the other alternating current for controlling the alternating current electroresponsive means, traflic governing means for each section controlled jointly by the two electroresponsive means associated with that section, a source of direct current and a source of alternating current, and means governed by the electroresponsive means of each section for supplying to the track circuits for the section next in the rear current from each source of one polarity or of the other polarity.

'7. A railway signal system comprising; a first, a second and a third consecutive track section over which traffic normally progresses in the order named; a direct current polarized track relay and an alternating current polarized track relay for each section each receiving current from the rails of the section, said direct current relays each effective to prevent the flow of alternating current therein and said alternating current relays each connected to the rails of the associated section by means efiective to prevent the flow of direct current therein, means governed by the direct current track relay for the third section when deenergized by a train occupying that section to supply direct current of reverse polarity to the rails of the second section, means governed by the direct current relay for the second section when energized to supply direct current of normal polarity to the rails of the first section, means governed by the direct current track relay of the third section when deenergized to disconnect alternating current from the rails of the second section, means governed by the direct current relay of the second section when reversed to disconnect the alternating current from the rails of the first section, a signal for the third section caused to indicate stop when its direct current relay is deenergized, a signal for the second section caused to indicate a restrictive indication when its direct current track relay is reversed and its alternating current relay is deenergized, and a signal for the first section caused to indicate a less restrictive indication when its direct current track relay is normal and its alternating current track relay is deenergized'.

8, A railway signal system comprising a stretch of railway track divided into sections, two polarized track relays one direct current and one alternating current for each section and each receiving energy from the rails of the section, said direct current relays each effective to prevent the fiow of alternating current therein and said alternating current relays each connected to the rails of the associated section by means effective to prevent the flow of direct current therein, means controlled by the direct current track relay for selectively supplying direct current of normal or reverse polarity to the rails of the section next in rear, means controlled jointly by both direct and alternating current track relays for selectively supplying alternating current of normal or reverse polarity or no current to the rails of such section next in rear; and a signal for each section controlled by the two track relays of that section and arranged to have a first aspect when the direct current track relay is deenergized, a second aspect when the direct current track relay is energized reverse and the alternating current relay is deenergized, a third aspect when the direct current track relay is energized normal and the alternating current track relay is de- 7 energized, a fourth aspect when the direct current relay is energized normal and the alternating current relay is energized reverse and a fifth aspect when both relays are energized normal.

9. In combination, a stretch of track having a track section, a signal to govern traffic through said stretch and capable of assuming several distinctive aspects, a polarized direct current track relay and a polarized alternating current track relay, each receiving energy from the rails of said section, operating circuits including neutral and polar contacts of both said relays-for selectively establishing the different aspects of said signal, a first pole-changer for reversibly supplying direct current to the rails of the section, a first trafiic controlled means responsive to traffic conditions in advance of the section to govern said first pole-changer, a second pole-changer for reversibly supplying alternating current to the rails of the section, and a second trafiic controlled means responsive to traflic conditions in advance of the section for governing said second polechanger.

10. A railway signal system comprising a stretch of railway track divided into track sections, a polarized direct current track relay and an alternating current polarized track relay for each section each receiving energy from the rails of the section, a repeating relay for each alternating current track relay, contacts operated by each direct current track relay to pole-change the direct current supplied to the rails of the section next in rear, contacts operated by each repeating relay to pole-change the alternating current supplied to the rails of such section next in rear, a signal for each section having several difierent aspects controlled by the track and repeating relays of that section, and said direct current track and repeating relay each characterized by retaining said pole-changing contacts closed during periods of pole-changing whereby signal flashing is avoided.

11. A railway signal system comprising a stretch of railway track divided into track sections, a polarized direct current track relay and a polarized alternating current track relay for each section each receiving energy from the rails of the section, a repeating relay for each section governed by the alternating current track relay for that section, contacts of each direct current track relay pole-changing the direct current supplied to the rails of the section next in the rear, contacts of each repeating relay pole-changing the alternating current supplied to the rails of the section next in the rear, whereby a distinctive control is effected for each of four consecutive track sections to the rear of an occupied section, and said direct current track relay as well as said repeating relay being characterized by retaining said pole-changing contacts closed during polechanging periods whereby successive tumbledown of the track relays to the'rear is avoided.

12. A railway signal system comprising a stretch of railway track, a signal located at the entrance of the stretch to govern traflic entering the stretch, said signal capable of displaying a stop indication and four different proceed indications having varying degrees of speed restrictions, a direct current relay and an alternating current relay, trafiic controlled means for governing the direct current relay and the alternating current relay, circuit means controlled jointly by said relays for selectively governing the indications of said signal and arranged in such a manner that the direct current relay is effective to provide certainrestrictive proceed indications in the event the alternating current is absent.

13. A railway signal system comprising; a first, a second, a third and a fourth track section over which trafiic normally progresses in the order named, two polarized track relays for each section one direct current and one alternating current and each receiving energy from the rails of the section, means controlled by the direct current track relay of the fourth section for discontinuing the supply of alternating current to the rails of the third and second sections when the fourth section is occupied, means including a back neutral contact of the direct current track relay for the fourth section for supplying direct current of reverse polarity to the rails of the third section, means including a front neutral contact of the direct current track relay for the third section for supplying direct current of normal polarity to the rails of the second section, means including a normal polar contact of the direct current track relay for the second section for supplying alternating current' of reverse polarity to the'rails of the first section, a signal for said first section, and means including a reverse polar contact of the alternating current track relay for the first section for'causing said signal to indicate that the fourth. section is occupied.

14. In combination, a stretch of railway track divided into a plurality of sections, a source of direct current and a source of alternating current, means governed by trafiic conditions in said stretch for supplyingdirect current of normal or reversepolarity to the rails of each section and for supplying alternating current of normal or reverse polarity to the rails of each section, a

direct"current polarized track relay connected across the rails of each section, and an alternating current polarized'track relay also receiving current from the rails of each section, a con denser connected in series with each alternating current track relay, and a signal foreach section governed jointly by the track relays receiving energy from the rails of that section.

15. In combination, a stretch of railway track divided into a plurality of sections, a source of direct current and a source of alternating current, means governed by traflic conditions in said stretch for supplying direct current to the rails of each section or for supplying alternating current to the rails of each'but not both simultaneously, a direct current track relay and an alternating current track relay connected across the rails of such section, a condenser connected in series with each alternating current track relay and a signal for each section governed jointly by the track relays associated with such section.

16. In combination, a stretch of railway track divided into. a plurality of sections, a source of direct current for supplying energy'to the rails at one end of each section, ,a source of alternating current for supplying energy to the rails at said one end of each section, said direct current and said alternating current being in series, means for governing both said direct current source and said alternating current source in accordance with traific conditions in said stretch, a direct current track relay and an alternating current track relay each receiving energy from the rails at the other end of each section, and a signal for each section governed track relays of that section.

17. In combination, a stretch of railway track divided into a plurality of sections, a source of direct current for supplying energy to the rails at one end of each section, a source of alternating current for supplying energy to the rails at said one end of each section and in multiple with the direct current source of that section, means for governing both said direct current source and jointly by the said alternating current source in accordance with trailic conditions in said stretch, a direct currenttrack relay and an alternating current track relay each receiving energy from the rails at the other end of each section, and asignal for each section governed'jointly by the track relays of that section.

18. A railway signal system comprising a stretch of railway track divided into sections, two polarized track relays one direct current and one alternating current for each section each receiving energy from the rails of the section, said direct current relays each efiective to prevent the fiow of alternating current therein and said alternating current relays each connected to the rails of the associated section by means effective to prevent the flow of direct current therein, means controlled jointly by the direct current track relay and the alternating track relay of each section for supplying either direct current or alternating current each of normal or reverse polarity but not both simultaneously to the rails of the section next in rear; and a signal for each section controlled by the two track relays of that section and arranged to have a first aspect when both track relays are deenergized, a second aspect when the direct current track relay is energized reverse, a third aspect when the direct current track relay is energized normal, a fourth aspect when the direct each section controlled jointly by said two track' relays for that section for governing the supply of current in such manner that either direct current or alternating current each of normal.

or reverse polarity but not both simultaneously is supplied to the rails of the section next in rear; and a signal for each section controlled by the two track relays of that section and arranged to have a first aspect when both track relays are deenergized, a second aspect when the direct current track is energized reverse, a third aspect when the direct current track relay is energized normal, a fourth aspect when the direct current track relay is deenergized and the alternating current track relay is energized reverse, and a fifth aspect when the direct current track relay is deenergized and the alternating current track relay is energized normal.

20. A railway signal system comprising, a stretch of railway track divided into track-sections, a signal for each section capable of ,displaying a stop indication and four different proceed indications having varying degrees of speed restriction, a direct current track relay and an alternating current track relay for each section each receiving energy from the rails of the section, means responsive to traffic conditions in advance of each section for supplying direct current or alternating current but not both simul taneously to the rails of that action, operating means including neutral and polar contacts of each of the relays of a section for selectively establishing the different indications of said signal, said operating means arranged in such a manner that the direct current track relay is effective to control the stop and certain restrictive proceed indications in the event of the absence of the alternating current.

21. In combination, a section of railway track, a signal for said section capable of displaying a stop indication and three successively less restrictive proceed indications, a polarized relay responsive only to energy of one character for governing the stop and the two most restrictive proceed indications, another relay responsive only to energy of another character for governing the least restrictive proceed indication, a source of energy of one character and a source of energy of said other character, and means effective when the section is unoccupied to reversibly supply energy from the source of said one character to said polarized relay or to supply energy from the source of said other character to said other relay in accordance with traffic conditions in advance of said section, said means being automatically effective to reversibly supply energy of said one character when the source of energy of said other character is absent.

22. In combination, a section of railway track, a signal for said section capable of displaying a stop indication and four successively less restrictive proceed indications, a first polarized relay responsive only to energy of one character for governing the stop and two most restrictive proceed indications, a second polarized relay responsive only to energy of another character for governing the two least restrictive proceed indications, a source of energy of said one character and a source of energy of said other character, and means efiective when the section is unoccupied to reversibly supply energy from the source of said one character to said first polarized relay or to reversibly supply energy from the source of said other character to said second polarized relay in accordance with trafiic conditions in advance of said section, said means being automatically eifective to reversibly supply energy of said one character when the source of energy of said other character is absent.

23. In combination, a section of railway track, a signal for said section capable of displaying a stop indication and three successively less restrictive proceed indications, a polarized relay responsive only to energy of one character for governing the stop and two most restrictive proceed indications, another relay responsive only to energy of another character for governing the least restrictive proceed indication jointly with said polarized relay, a source of energy of said one character and a source of energy .of said other character, and means controlled by;traiiic conditions in advance of the section effective when said section is unoccupied to reversibly supply energy from only the source of said one character to said polarized relay or to supply energy from the source of said other character to said other relay simultaneously with the supply of energy from said one source to said polarized relay.

24. In combination, a section of railway track, a signal for said section capable of displaying a stop indication and four successively less restrictive proceed indications, a first polarized relay responsve only to energy of one character for governing the stop and two most restrictive proceed indications, a second polarized relayresponsive only to energy of another character for governing the two least restrictive proceed indications jointly with said first relay, a source of energy of said one character and a source of energy of said other character, and means controlled by traflic conditions in advance of said section effective when the section is unoccupied to reversibly supply energy from only the source of said one character to said first polarized relay or to reversibly supply energy from the source of said other character to said second polarized relay simultaneously with the supply of energy from said one source to said first relay.

25. In combination, a section ofrailway track, a signal for said section capable of displaying a stop indication and three successively less restrictive proceed indications, 'a polarized track relay responsive only to energy of one character connected across the rails at one end of the section, another track relay responsive only to energy of another character also connected across the rails at said one end, said polarized track relay controlling the stop and two most restricl tive proceed indications and said other relay controlling the least restrictive proceed indication, a source of energy of said one character and a source of energy of said other character, and means for reversibly supplying energy from the source of said one character to the rails at the other end of said section or for supplying energy from the source of said other character to the rails at said other end in accordance with trafiic conditions in advance of said section, said means being automatically effective to reversibly supply energy of said one character when the energy of said other character is not available.

26. In combination, a section of railway track, a signal for said section capable of displaying a stop indication and four successively less restrictive proceed indications, a first polarized track relay responsive only to energy of one character connected across the rails at one end of the sec tion, a second polarized relay responsive only to energy of another character also connected across the rails at said one end, said first relay for controlling the stop and two most restrictive proceed indications and said second relay for controlling the two least restrictive proceed indications, a source of energy of said one character and a source of energy of said other character, and means for reversibly supplying the rails at the other end of the section with energy from said one source or for reversibly supplying therails at said other end with energy from said gy of said one character when the energy of said other character is not available. 1

27. In combination, a section of railway track, -a signal for said section capable of displaying a stop indication and three successively'less restrictive proceed indications, a polarized track relay responsive only to energy of one character connected across the rails at one end of the section, another track relay responsive only to ener- -gy of another character also connected across the rails at said one end, said polarized relayfor governing the stop and two most restrictive proceedindications and said other relay governing the least restrictive proceed indication jointly with said polarized; relay, a source of energy of said one character and a source of energy of said other character, and means controlledby trafiic conditions in advance of the section for reversibly supplying energy to the rails at the other end of the section from only the source of said one character or to supply energy to the rails at said other end from said other source simultaneously with the supply of energy from said one source.

28. In combination, a section of railway track, a signal for said section capable of displaying a stop and four successively less restrictive proceed indications, a first polarized track relay responsive only to energy of one character connected across the rails at one end of said section,

a second polarized track relay responsive only ling' the two least restrictive proceed indications of said one character or to reversibly supply energy to the rails at said other end from the source of said other character simultaneously with the supply of energy'from said one source.

29. In combination, a section of railway track, a pair of conductors for said section, a first control means responsive only to energy of one character connected across said conductors, a second control means responsive only to energy of another character, means connecting said second control means in multiple with said first control means, means for supplying said conductors with only energy of said one character or with energy of said other character simultaneously with energy of said one character in accordance "with traific conditions in advance of said section,

and traiflc governing means for said section governed by said two control means. a r

30. In combination, a section of railway track, a pair'of conductors for said section, a direct current'relay connected across said conductors,

an alternating current relay connected in multiple with said direct current relay, means for supplying said conductors with only direct current or with alternating current simultaneously with direct current in accordance with traffic conditions in advance of said section, and a signal for said section governed by said two relays. V .1

JAMES J. VANHORN.