US1117559A - Railway signaling. - Google Patents

Description

W. F. FOLLBTT.

RAILWAY SIGNALING.

APPLICATION FILED NOV. 12, 1912- 1,1 17,559, Patented Nov. 17, 191i 2 SHEBTSBHEET 1.

wlTNE/sjs j/ INVENTOR THE NORRIS PETERS c0. PHO10-LlTHf7.. WASHINGTON. n. C,

W. F. POLLETT RAILWAY SIGNALING.

APPLICATION nun NOV. 12, 1912.

1, 1 17,559. Patented Nov. 17,1914.

2 SHEETS'SHEET 2.

WW WaZaLa-WkTa-M THE NORRIS PETERS CO.PHOTOL!1HU,WA5HING You. 11 v.

TE STATES PATENT OFFICE.

WALDO F. FOLLETT, OF NEW HAVEN, CONNECTICUT, ASSIGNOR TO THE UNION SWITCH & SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A CORPORATION OF PENN- SYLVANIA.

RAILWAY SIGNALING.

Specification of Letters Patent.

Patented Nov. 17, 1914.

To all whom it may concern:

Be it known that I, /VALDo F. FoLLn'r'r, a citizen of the United States, residing at New Haven, in the county of New Haven and State of Connecticut, have invented certain new and useful Improvements in Railway Signaling, of which the following is a specification.

My invention relates to railway slgnalmg systems.

I will describe one form of railway signaling system embodying my invention and will then point out the novel features thereof in claims.

In the accompanying drawings Figure 1. is a diagrammatic view showing one fornrof railway signaling system embodying my nvention, and Fig. 2 is a view showing diagrammatically that the common wire for each block section is electrically disconnected from the common wire for each adjacent block section.

Referring to the drawing, 1, 2, 3 and l designate four parallel tracks of a railway, here shown as being an electric railway. It is understood that the railway is provided with a suitable source of propulsion current and with a third rail or trolley wire, but for the sake of simplicity these parts are omitted from the drawing. The track rails oi each track are divided into block sections L, K and N by any suitable means; as here shown these block sections are formed by insulated joints 66 in both track rails of each track. Since the railway is an electric railway, the track rails are preferably included in the circuit for the propulsion current. I provide inductive bonds 55 by means of which the propulsion current is conducted around the insulated joints 66 from the track rails of one block section to the track rails of the adjacent block sections.

Traiiic along the tracks 1, 2, 3 and 4: is normally in the direction indicated by the arrows in these tracks. Traffic through blocksection K over tracks 1 and 3 is governed by signals S and S; trailic through block section K over tracks 2 and i is governed by signals S and S similarly trafiic over tracks 1 and 3 through block section L is governed by signals S and S and traffic over tracks 2 and 4 through block section l is governed by signals S and S Each of these signals is adapted to give three indications, namely, danger, caution and clear as here shown, each signal compriscs two arms, a home arm it and a distant arm (Z, although I do not wish to be limited to this particular type of signal. It is understood that one arm three-position signals may equally well be employed. It is also understood that regardless of the type of signal employed, each signal is provided with two controlling circuits, viz., a caution indication circuit and a clear indication circuit. In the case of two-arm two-position signals as shown in the drawing, the cantion indication circuit controls the controlling apparatus for the home arm 72,, and the clear indication circuit controls the controlling apparatus :t'or the distant arm (Z.

Alternating signaling current for the signaling system is supplied by power mains M extending along the trackway, which mains are supplied from a suitable source, such as a generator 77. The signaling current should differ in character from the propulsion current; if the propulsion current is alternating, then the signaling current difi'ers therefrom preferably in tli'requency. In the present case I will assume that the propulsion current is 25 cycle current and that the signaling current is (30 cycle current.

Located adjacent each set of signals is a transformer T or T, whose primary is connected with the power mains M and whose secondary is connected with local distributing wires X and Y or X and Y.

Each block section of each track is provided with a track circuit comprising as usual a source of current connected with the track rails adjacent one end of the block section and a track relay connected with the track rails adjacent the other end of the For example, the source of block section. current for the track circuit for block section K of track 3 is a transformer 56 whose primary is connected with wires Xand Y and whose secondary is connected with the track rails by wires 58 and 5%.). The track relay R" of this track circuit is as here shown of a polyphase type comprising one winding IV connected with the track rails by wires 60 and 61 and another winding V track winding to close its contacts. Several types of relay of this character are known in the art and no further explanation is required. The sources of current for block sections K of tracks 1, 2 and 4: are respectively transformers 57, 64 and 65, andithe track relays for these track circuits are re spectively relays R, R and B, each of which relays may be similar to relay R For the control of each signal I provide a signal relay. Signal S is controlled by relay B, signal S by relay D, signal S by relay F and signal S by relay H. Each of these signal relays is of a 3-position type and as here shown is of a single phase type comprising two members, an armature a and a field winding f. Each of these relays is so arranged that when the armature a is in one extreme position the contact fingers engage the upper contact points; when the armature is in the other extreme position, the contact fingers engage the lower contact points and when the armature occupies the middle position all the contacts are open. The circuit for home arm h of each signal is controlled by the upper contact fingers 67 and 68 of the corresponding relay, and the circuit for distant arm (Z is controlled by the two lower contact fingers 69 and 70 For example, the circuit for the home arm 71 of signal S is from wire Y through wire 13, upper or lower point of contact 67, wire 14., controlling apparatus for home arm h,

wire 15, upper or lower point of contact 68,

wire 16 to wire X. The circuit for the di tant arm (Z of signal S is from wire Y through wire 13, upper point of contact 69, wire 17, controlling apparatus for arm (Z, wire 18, upper point of contact 70, wire 16 to wire K. It will be seen therefore that when the ari'nature a of relay B occupies its m ddle position the circuits for both arms of s gnal are open so that the signal then in d cates danger; when. the armature a occu pies its lower position so that the lower points are engaged by the contact fingers, the circuit for home arm h is closed and the circuit for the distant arm (Z is open so that the signal then indicates caution; but when armature a occupies its other extreme position so that the upper points of the relay are engaged by the contact fingers, the circuits for both arms are closed so that the signal then indicates clear. The circuits for each of the signals S, S and S are similar. to those just traced for signal 53 hence they need not be traced herein. The field wind ing f of each signal relay is connected with wires K, Y, or X, Y. For example the field winding 7'' of relay B is connected with wires X, Y, by. wires 78 and 79. The armature winding (4 of each signal relay is connected with a line circuit extending through the block section K and energized from the source of signaling current at the opposite end of the block section. Each of these line circuits is provided with a pole changer P, P, P or P respectively, for reversing the polarity of the current in the line circuit, these pole changers being operatively connected respectively with the home arm A, of signals S S S3 and S Each line circuit also includes a transformer A, C, E or Each line circuit comprises a line wire individual to that circuit and a common wire 7, which common wire is common to all of the line circuits for block section K and is not connected with the common wire of either of the adjacent block sections L or N. The fact that the common wire 7 of each block section is electrically disconnected from the corresponding wire of each adj acent block section is indicated in Fig. 2. The line circuit for relay B includes polechanger P and transformer A. The circuit of the primary of this transformer is as followsfrom wire Y through wire 51, contact of pole changer P wire 52, primary of transformer A, wire 53, contact of pole changer P wire 54, to wire X; the secondarycircuitfor this line circuit is from the secondary of transformer A throughwires 5 and 6, common wire 7, wires 8 and 9, contact of track relay R wire 10, armature a of relay B, wire 11, contact of relay R wire 12 to the secondary of transformer A. The line circuit for relay 1) is similar to that just traced for relay B and includes pole changer P, transformer C, line wires 27 and 7, and the contacts of track relay Bi. Similarly the line circuit for relay F includes pole changer P transformer E, line wires 4:7, and 7 and the contacts of track relay The line circuit for relay H similarly includes pole changer P transformer G, line wires 38 and 7, and the contacts of track relay R The operation of the system may be sufficiently explained by explaining the eifect on the circuits and apparatus of the passage of a car or train along track 3. WVhen the block sections L and K of track 3 are unoccupied, as shown in the drawing, track relay R5 is closed thereby holding closed the line circuit for signal relay B. Home .arm h of signal S is in the inclined position so that pole changer l? is in such position that the polarity of the current in the line circuit for relay B causes the upper points of this relay to be engaged by the contact fingers so that signal S indicate clear. If now, a car or train enters block section K from block section N it deenergizes track relay R thereby opening the line circuit for relay B the armature of which then moves to its middle position; this opens the circuits for both the home and distant arms of signal S so that this signal changes to danger indication. As the car or train passes out of block section K into block section L it similarly causes signal S to change to danger indication whereby reversing pole changer P Track relay R now closes thereby closing the line circuit for signal relay B but the polarity of the current in this line circuit having been reversed by pole changer P, this relay is energized in such direction that its lower points are engaged by the contact fingers thereby closing the circuit for home arm h of signal S, but holding open the circuit for the distant arm d of this signal so that signal S then indicates caution. As the car or train passes out of block section L it causes signal S to change to caution indication, thereby again reversing pole changer P, so that the polarity of the current in the line circuit for signal relay B is then such as to cause the upper points of this relay to be closed thereby causing signal S to again indicate clear. The operation of the apparatus foreach of the other three tracks is the same as that which I have just explained for track 3, hence no further explanation is necessary.

The circuits which I have hereinbefore explained are so arranged that a false clear signal indication cannot be caused by broken wires, crosses or electromagnetic or static induction. I will now describe the effect on the system of these abnormal conditions. If any one of the line wires 12, 27, 47 or 38 should become open, the 3-position signal relay controlled by such wire will be deenergized so that its contacts will assume their middle position, thereby causing the signal controlled by that relay to indicate danger. If the common wire 7 becomes open the eflect is as followsif block sections K and L of track 3 are unoccupied, current will pass from the secondary of transformer A, through wires 5 and 6, wire 34 to the point where it divides into wires 35 and .44, through wires 35 and 44 in multiple, contacts of relays R and R wires 36 and 45 in multiple, armatures of signal relays H and F in multiple, wires 37 and 46 in multiple, contacts of track relays R and R in multiple, wires 38 and 47 in multiple to secondaries of transformers G and E, wires 32 and 43 in multiple, wire 33, wire 8 to point where it divides into wires 9 and 24, thence through wire 9, contact of relay R wire 10, armature of relay B, wire 11, contact of relay R wire 12 to secondary of transformer A. i It will be seen, therefore, that if common wire 7 is open and block sections K and L of track 3 are unoccupied, current from transformer A still passes through armature of relay B in the normal direction so that this relay is still energized to cause signal S to indicate clear. Current from the secondary of transformer C passes through wire 23, then it flows in common with current from transformer A through wires 6 and 34, wires 35 and 44 in multiple,

contacts of relays R and R in multiple, wires 36 and 45 in multiple, armatures of signal relays H and F in multiple, wires 37 and 46 in mutliple, contacts of relays R and R in multiple, wires 38 and 47 in multiple, secondaries of transformers G and E in multiple, wires 33 and 8; from thence the current from transformer C alone passes through wire 24, contact of relay R, wire 25, armature of relay D, wire 26, contact of relay R, wire 27 to secondary of transformer C. It will be seen, therefore, that current from transformer C still passes through signal relay D in the normal direction so that this relay is still energizedto cause signal S to indicate clear. Current from transformer A cannot energize relay D because wire 27 leading from that relay does not connect with transformer A; and similarly current from transformer C cannot energize relay B because wire 12 leading from that relay does not connect with transformer C. Hence, when common Wire 7 is open and block sections K and L of tracks 3 and l are unoccupied, the signals are not affected.

If, while common wire 7 is open, a train enters either track 3 or 1 of block section K, signal S or S for that track will change to danger and the other signal S or S will not be affected. lVhen such train passes from block section K into block section L,

the corresponding signal S or S changes to caution. For example, assume that track 3 of block section L is occupied. The 130- larity of transformer A is then reversed with respect to transformer C, and current then flows from the secondary of transformer A through wire 12, contact of relay R wire 11, armature of relay B, wire 10, contact of relay R wires 9 and 24, contact of relay R, wire 25, armature of relay D, wire 26, contact of relay R, wire 27, secondary of transformer C, Wires 23 and 5 to secondary of transformer A. The direction of this current in relay B is such1as to energize that relay in such direction as to cause signal S to indicate caution, and the direction of this current in relay D is such as to energize that relay in such direction as to cause signal S to indicate clear. Hence, the proper operation of these signals is not interfered with, and the opening of common wire 7 cannot cause a false clear signal. The circuits for signal relays H and F from transformers G and E in case common wire 7 becomes open are similar to those just explained for signal relays B and D.

Assume that any one of the wires 12, 27, 47 or 38 becomes crossed with the common wire 7, as for example, that line wire 12 be comes connected with common wire 7, as indicated at 71 on the drawing. Current will then flow from the secondary of transformer A through wires 5, 6 and 7 to the cross 71,

at which point it. divides, part passing through wires 7, S and 9, contact of relay R wire 10, relay B, wire 11, contact of relay R, wire 12 to the cross 71; thence through wire 12 to the secondary of transformer A; the remainder of the current will flow from wire 7 through the cross 71 to wire 12, thence through wire 12'to transformer A. If the cross 71 is of sufliciently low resistance such a large portion of the current will pass through the cross that the signal relay B will be deenergized and signal S controlled thereby will indicate danger. If however the cross 71 is not of sufliciently low resistance, the operation of the system will not be interfered with. A similar condition would exist in case of a cross between common wire 7 and any one of the remaining line wires.

Assume now that a cross exists between any two of the wires 12, 27, 17 and 38, for example, between wire 12 and 27 as indicated at 72 on the drawing. Current would then flow from the secondary of transformer A through wires 5, 6,7, 8 and 9, contacts of relay R wire 10, relay B, wire 11, contact of relay R wire 12, to the point of cross 72; if transformer C is energized with the same polarity, current will flow from the sec ondary of this transformer through wires 23, 6, 7, 8 and 24, contact of relay R, wire 25, relay D, wire 26, contact of relay R, wire 27 to the point of cross 72; these two currents at the point 72 have the same polarity and the same potential, hence, they will flow through their respective wires 12 and 27 to the secondaries of their respective transformers A and C. Hence, when the transformers A and C have the same polarity the cross 72 will have no effect on the, signaling system. Assume however, that the cross 72 exists and that the polarity of the transformers A and C is opposite; for example, assume that the polarity of transformer A remains as before but that the polarity of transformer C is reversed by the presence of a car or train in block section L of track 1. Then current attempts to flow as hereinbefore explained from transformer A through wires 5, 6, 7, etc., to relay B and wire 12 to cross 72; at the same time current will attempt to flow from the secondary of transformer C through wire 27 to the point 72. These two currents have opposite polarity at the point of the cross 72, so that the current from transformer A which was supposed to have passed through relay B is checked by the counter current through wire 27, and it passes instead through wires 5 and 23 to the right hand of the secondary of transformer C, through this secondary to wire 27 to cross connection 72, wire 12, back to the left hand side of the transformer A, with the result that the two transformers A and G are short circuited and practically no current passes through the signal relays B or D; These relays are therefore deenergized causing signals S and S to indicate danger. I

I will now describe the effect on the signaling system of electromagnetic induction from an adjacent alternating current power line. Assume that such power line extends along the railway parallel therewith and that it is carrying a heavy 25 cycle propulsion current. This current will create an induced voltage upon the line circuits of the signal system by electro-magnetic induction. The strength of the induced voltage is dependent upon the strength of the propulsion current, the distance between the propulsion lines and the signal lines, and the continuous length of the signal lines. In order to-break the continuity of the signal lines and thereby limit-the possible values of the induced voltage, the signal lines for each block section, including the common wire 7 are made electrically independent of the signal lines for the adjacent block sections as hereinbefore explained. Assume that the. line circuits are sufficiently insulated from the ground to withstand this impressed voltage and also assume that at a given instant the induced current in the line circuits is flowing in the direction indicated by the'arrow 73. This induced current has a tendency 'to flow through wire 12, contact of relay R wire 11 to armature aof relay B; simultaneously an equal induced current has atendency to flow through wire 7 in the direction of the 311'. row 7 3,through wires 8 and 9,contact of relay R wire 10 to the other terminal armature a of relay B. These two currents will neutralize at the armature of relay B, hence, no induced current would fiow through this armature, and the induced current would have no effect on the signaling system. A similar condition would existas to the three remaining line circuits and signal relays.

Assume that the conditions electrically are the same as just described with the exception that line wire 12 is grounded at the extreme ends of the block section, as for example, at the'points 74: and 7 5. VVhen the current surge is in the direction indicated by arrow 7 3,,the induced current would neutralize as heretofore explained but there will be another circuit established by the induced current as follows from wire 12 to the ground at point 75, thence through the ground to pointv 74 and back to wire 12; also there will be a similar circuit established from wire 7 through wiresv 8 and 9, contact of relay R wire 10, relay B, wire 11, contact of relay R wire 12 tothe ground at point 75, thence through the ground to point 74, to wire 12, secondary of transformer A, wires 5 and 6 to wire 7. Thus an induced current flows through the armature of relay B. When a car or train occupies block K of track 3, this current will not affect the relay B because the contacts of track relay R will be open thus interrupting the circuit for the induced current just recited. Assume now that with the conditions just described, block section K is free but that a car or train occupies block section L of track 8, thereby changing the polarity of the line circuit of signal relay B; this would under normal conditions cause signal S to indicate caution. Since the contacts of track relay R are now closed the induced current wouldnow pass through the armature of relay B as just explained. The conditions which now exist would be a (30 cycle signalingcurrent and a 25 cycle pro pulsion current in both the field and the armature of relay B, the 60 cycle signalin current being the normal energy suppliec from the signal system. The 25 cycle propulsion current would pass through the armature of relay B, as cited above, and in passing through transformer A would cause 25 cycle energy in the power wires X and Y, which, in turn, would cause 25 cycle current in the tracks through the track transformers 5G and 57, and through'transformer T into the power mains M, thence through transformer T into wires X and Y, and thence into the field of relay B. The effect of this would be to reverse the torque of the armature of relay B. At the same time, the 25 cycle energy in the frequency track relay would cause the contacts of the track relay to open, thus deenergizino relay B. The interrupting of the circuit through the armature of relay B would also interrupt the induced current, eliminating the effect of 25 cycle energy upon the instruments in question, and they would immediately assume their former position by the 60 cycle energy present. lVith the establishment of the former position of the instruments, the 25 cycle circuit would be reestablished. Thus it will be seen that the contacts of relay B would vibrate between this former position and neutral position, thus causing the signal S to give either the caution indication or danger indication.

At the instant when the direction of the surge of induced current in the line wires is as indicated by arrow 76, the effect on the signaling system would be the same as hereinbefore described, except that the direction of the flow of the current would be reversed at the same given instant.

As for static induction the signal line wires would be continuously charged statically from the adjacent propulsion line up to a voltage dependent upon the voltage of such line and upon the break-down insulation resistance of the line wires of the signaling system. By the introduction of lightning arresters having a suitable predetermined break-down resistance, which resistance is lower than the break-down re sistance of the signal line wires, these line wires could be constantly drained of the voltage impressed statically above the breakdown point of the arresters.

Although I have herein shown and described only one form ofsignaling system 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 invention.

Having thus described my invention, what I claim is 1. In combination, a block section of a railway track, a signal located adjacent the entrance end of the section and adapted to give three indications, power mains extending through the section, a source of alter nating signaling current for said power mains, a main transformer located adjacent each end of the section, the primary of each main transformer being connected with said power mains, electromagnetic means for controlling said signal and comprising two windings one of which is constantly connected with the secondary of the main transformer at the entrance end of the section, a line circuit comprising two line wires connected with the other winding of said electromagnetic means and extending through the section, a line transformer whose primary is connected with the secondary of the main transformer at the exit end of the section and whose secondary is connected with said line wires, means for reversing the connection of the primary of the line transformer with the secondary of the last-mentioned main transformer, said electromagnetic means being responsive to said reversals of connection, and a track circuit for the section including a track relay for controlling said line circuit.

2. In combination, a railway comprising two parallel tracks over which traflic moves in the same direction, a block section for each track, a signal for each block section adapted to indicate danger, caution and clear, a three-position signal relay for the control of each signal, a source of alternating signaling current, a line circuit for each signal relay each comprising a line wire individual to such circuit and a commonwire common to both circuits, a transformer for each line circuit whose primary is connected with said source of signaling current and whose secondary is connected with the line circuit, a pole-changer for each line circuit for reversing the current in the line circuit with respect to the source, and a track circuit for each block section each including a track relay for controlling the line circuit of such block section.

3. In combination, a railway comprising two parallel tracks over which traflic moves in the same direction, a plurality of successive block sections for each track, the block sections of each track being substantially oppositely located, signals for the block sections adapted to indicate danger, caution and clear, a three-position signal relay for the control of each signal, a source of alternating signalingcurrent, a line circuit for each signal relay each line circuit comprising a line wire individual to such circuit and a common wire common to the line circuit of the oppositely located block section of the other track, a transformer for each line circuit whose primary is energized from said source of signaling current and whose secondary is connected with the line circuit, means controlled by each signal for reversing the current in the line circuit for the block section in the rear relative to the said source, and a track circuitfor each block section each including a track relay for controlling the line circuit of such block section.

4. In combination, a railway comprising a plurality of parallel tracks, a block section for each track, a signal for each block section adapted to give three indications, a three-position signal relay for each signal for the control thereof, a source of alternating signaling current, a line circuit for each signal relay each comprising a line wire individual to such circuit and a common wire common to all of the line circuits, a transformer for each line circuit whose primary is connected with said source of signaling current and whose secondary is connected with the line circuit, a pole changer for each line circuit for reversing the current in the line circuit with respect to the source, and a track circuit for each block section each including a track relay for controlling the line circuit of such block section.

5. In combination, a railway comprising a plurality of parallel tracks, each track being divided into a plurality of successive block sections and the block sections of each track being substantially opposite those of the other track or tracks, signals for the block sections adapted to indicate danger, caution and clear; a three-position signal relay for the control of each signal, a line circuit for each signal relay extending through the block section, a source of altertrack rails of each block section for controlling the line circuit of the block section.

6. in combination, a railway comprising a plurality of parallel tracks, each track being divided into a plurality of successive block sections and the block sections of each track bein substantially opposite those of the other track or tracks, signals for the sections, a line circuit for each block section of each track extending through the block section, each line circuit comprising a line wire individual to the circuit and another line wire common to the line circuits of the opposite block sections, said commonwire for each set of block sections being electrically insulated from the common wires'for the adjacent sets of block sections, means controlled by each line circuit for controlling the signal for the corresponding block section, and a track relay connected with the track rails of each block section for also controlling the signal for the block section.

7. In combination, a railway comprising a plurality of parallel tracks, each track being divided into a plurality of successive block sections and the block sections of each track being substantially opposite those of the other traclr or tracks, signals for the sections, a line circuit for each block section for the control of the signal for such section, each line circuit extending through the section and comprising a line wireindividual to the circuit and another line wire common to the line circuitsof the opposite block sections, the said common wire for each set of oppositely located block sections being electrically insulated from the common wires for the adjacent sets of block sections. 7

8. In combination, a railway comprising a plurality of-parallel tracks, each track being divided into a plurality of successive block sections and the block sections of each track being substantially opposite those of the other track or tracks, signals for the sections, a line circuit for each block section for the control of the signal for such section, each line circuit extending through the section the line circuits for each set of oppositely located block sections being electrically insulated from the line circuits for the adjacent sets of block sections.

9. In combination, a railway comprising two tracks over which traflic movesin the same direction, a block section for each track, a signal for each block section and adapted to give three indications, electromagnetic means for each signal for the control thereof, a source of alternating signaling current, a line circuit for the electromagnetic means for each signal, each line circuit comprising a line wire individual to the circuit and a common wire common to both circuits, a transformer for each line circuit whose primary is connected with said source and whose secondary is connected with the common wire and with the line wire individual to the circuit, a pole-changer for each line circuit for reversing the connection of the primary of the correspond ing transformer thereofwith the source, each electromagnetic means belng responsive to such reversals, and a track circuit for each block section including a track relay 10 for controlling the line circuit for the section.

In testimony whereof I afiix my signature in presence of two witnesses.

WALDO F. FOLLETT. Witnesses:

GEORGE Lnn'rn PEGK, ELMER B. MYERS.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, I). O."

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