US2313468A - Railway signaling system - Google Patents

Description

March 1943- o. s. FIELD- RAILWAY SIGNALING SYSTEM Fild Feb. 14, 1941 2 Sheets-Sheet 1 FIGJ FIG-.2.

IINVENTO March 9, 1943. o, s, FIELD RAILWAY SIGNALING SYSTEM 2 Sheets Sheet 2 Filed Feb. 14, 1941 1 INVENT' Patented Mar. 9, 1943 RAILWAY SIGNALING SYSTEM Oscar S. Field, Rochester, N. Y., assignor to General Railway Signal Company, Rochester,

Application February 14, 1941, Serial No. 378,966

11- Olaims. (Cl. 246-53) This invention relates in general to railway signaling systems and has more particular reference to wayside signaling systems employing type SC search light type signals.

The type SC search light signal is constructed and operates as disclosed in the Field application, Ser. No. 361,060, filed October 14, 1940.

This type SC signal has a single spectacle carrying a plurality of colored glasses through one of which at a time light from a single light source is directed to give a signal indication. The spectacle'is moved to various indicating positions by two separate mechanisms or relays which also operate various contacts and because of this construction, many of the usually employed relays such as line relays, repeating relays, etc., generally used in signaling systems, can be dispensed with since the operating mechanisms of the signals themselves can serve the added function of these otherwise necessary relays.

Further objects, purposes and characteristic features of this invention will appear as the description progresses, reference being made to the accompanying drawings, showing solely by way of example, and in no way whatsoever in a limiting sense, several forms of the invention. In the drawings:

Fig. l is a diagrammatic representation of one lorm of the invention.

Fig. 2 is a diagrammatic representation of a second form of the invention.

Fig. 3 is a diagrammatic representation 'of a signaling system employing alight signal of the type SA form and is shown forthe purpose of clarifying the disclosure of the invention.

Fig. 4. is a diagrammatic representation of a third form of the invention.

In Fig. 1 is shown an application of the type SC signal used in a signaling system of the polarized type in which no line wires are employed. In Fig. l, the track rails 6 comprising a stretch of single track, are separated into track sections by insulating joints I to form sections, the complete section 2 with the entrance end of section 3 and the exit end of section I being shown, trafiic being east bound as'indicated by arrow 8 Connected across the exit end of each track section is a battery B2 controlled by a pole changer having contacts 2| and 22 of the relay RYE. of signal S2 which is a signal of the search light SC type. The current feed to the exit ends of the sections include suitable adjustable reactances 23.

Connected across the entrance end of each track section, as section 2 is a track relay TR2 which is shown as of the polar retained neutral type, and can be as disclosed, for example, in the Bennett patent, No. 1,969,058, granted August 7, 1934. This retained type of relay is constructed as diagrammatically shown to retain its neutral contact 24 against releasing when the energizing polarity is changed so as to cause its polar contacts 25 and 26 to move from one side to the other.

The signal employed in this form of the invention and denoted by S2 has a spectacle SP operated by a red-yellow relay RYR and by a yellow-green relay YGR in the manner as described above.

With track section 2 unoccupied as shown, the signal assumes the position as shown to display the green indication, the two control relays being energized as is obvious from the drawings.

If we assume that a train occupies section 2 the track energy will be shunted away from the trackrelay TRZ to cause its contact fingers 24, 25 and 25 to assume their retracted positions, whereby to deenergize both of the operating relays of the signal and cause it to move to a position to display its red indication.

With relay RYR deenergized, what can be termed reverse polarity is placed on the upper rail of the section to the rear, through contact finger 22 and back point, etc., whereby to cause the signal atthe entrance to section i to display its yellow indication. With reverse polarity energy on the track, the track relay moves its polar armature and fingers to the right, whereby to energize the red-yellow relay and deenergize the yellowgreen relay.

The block to the rear of block I will receive normal polarity on the upper rail so as'to energize both of the corresponding signal relays and cause the signal to display a green indication. The same occurs for all signals to the rear thereof, providing no occupancy be present. a

The track relays as relay TR2 have been shown as of the polar retained neutral type but in many cases, the red-yellow relay of the signal in question is slow enough to release or can be made slow enough to release so that the time during which the red-yellow relay is deenergized due to the neutral contact finger as 24 of the track relay is away from its front contact is not long enough to allow it to release and produce a flash of the red indication. If the red-yellow relay is not slow enough in releasing to bridge this period of deenergization the retained type of track relay can be used whereby the deenergization of relay RYR is merely of the duration while the polar contacts move from one position to the other. These polar contacts move very rapidly and are of the snap action type whereby there can be no chance whatsoever of a flash of the red occurring under the conditions referred to just above.

In Fig. 2 there is shown a slightly modified form of the invention whereby a polarized signal of the SC type is employed in connection with polarized track circuits.

In this form of invention a stretch of single track is constituted by track rails fi 'having insulating joints 1 with travel being considered in an easterly direction as indicated by arrow 8 In this modification, a signal as S2 is positioned at the entrance end of each section and is of the SC type. This signal difiers slightly from that described above in that the yellowgreen relay YGR. is polarized by a permanent magnet 30 whereby to cause the yellow-green relay to respond only to energization of what may be termed normal polarity. The red-yellow relay RYR is non-polarized but is connected across the output side of a full-wave rectifier 3i! whereby to prevent it releasing its armature when energizing polarity is changed. The operation of this polarized type of signal is disclosed in detail in theField application referred to above. In brief, the signal spectacle SP is biased to display the red indication, is moved to display the yellow indication when the signal is energized by current of reverse polarity and to display the green indication when the signal is energized with current of normal polarity.

The parts are shown in Fig. 2 in the positions and conditions they assume when the track is unoccupied. Current of normal polarity from a battery (not shown) is connected to the upper rail by wire 3| to energize track relay TR2 to pick up its neutral contact finger 3| and position its polar contact finger 32 to the left. This applies current of normal polarity to the windings of the two signal control relays, through a circuit including polar contact finger 32 of relay TR2 to thereby position the spectacle of the signal S2 to display its green indication.

If we now assume that section 2 be occupied by a vehicle, relay TRZ is deenergized to deenergize both of the operating relays of the signal S2 to thereby cause it to display its red indication.

With relay RYR. deenergized, current of reverse polarity is applied to the exit end of block I immediately to the rear to thereby cause the signal for this block to display its yellow indication.

The block immediately to the rear of block l and all blocks to the rear thereof, assuming unoccupancy, are supplied with normal polarity since the red-yellow relays are energized, whereby to cause the signals to display their green indications.

It is clear that the signal upon changing from yellow to green due to a change of the polarity applied to the track section, is momentarily deenergized. The red-yellow relay of such signal is slow in releasing due to the rectifier connected across its winding whereby to bridge over this brief period of deenergization and retain the yellow indication until the green indication is put in force, thus to avoid any flash of the red indication occurring between a yellow and green indication. It also can be noted that no relays or other apparatus is required in addition to the signal of this SC type, except the sources of energy and connecting wires and the track relays.

In the form as shown in Fig. 2, the track relay has been shown as of the polar retained neutral type but this may not be necessary and particularly so in the polarized type of signal as shown in Fig. 2, wherein the rectifier 30 imparts slow release characteristics to the red-yellow rey.

Furthermore, in the form of Fig. 2, the track relays can be dispensed with and the signal energizing circuit connected across the track rails.

Referring now to Fig. 3, there is here shown a stretch of track constituted by track rails 6 divided intoisolated track sections by insulating joints 1 with traffic considered as moving eastward, as indicated by arrow 8 To exemplify this form of invention, the signal is shown as of theSA type so as to aid an understanding of the advantages thereover of the SC type of signal employed in a corresponding signaling system. Between successive signals as S2 and S3 there are two separate track sections, as 2 2 constituting a split section in a well recognized manner. With such a split section a track relay as TR2 is placed across each end of the split section with intermediate insulating joints and track batteries 40 and 4|.

The type SA signal here employed is constructed and operates as described in the Murphy patent, No. 2,156,637, granted May 2, 1939. Briefly, it includes a spectacle 42 carrying colored roundels G, R and Y, respectively colored green, red and yellow! and positioned in the order named. That is, the red roundel is between the green and yellow roundels. The spectacle is biased to normally assume a position opposite a light source 42a, so as to display its red indication. Upon being energized with current of reverse polarity its winding 43 operates the spectacle to a position to display its yellow indication, and when energized with current of normal polarity the spectacle is moved to display its green indication. The spectacle on movingoperates contactors 44 and 45 by means of pins 46 and 41 to place energy on a circuit including wire 48 when it is in either its green or its yellow indicating position.

Associated with the signal is a repeater relay YGP2 which is connected in the circuit including wire 48 whereby to constitute a yellowgreen repeater relay and be energized when its signal is displaying either yellow or green. This repeater relay, when energized, places current of positive polarity on the signal winding immediately to the rear and when deenergized places current of negative polarity on this winding through a circuit including front contacts in series of the two track relays of the section to the rear.

For example, the repeater relay YGP3 is shown as being energized whereby to place current of normal polarity on winding 43 of signal S2 through a circuit including contact finger 49 and front point of repeater relay YGP3 contact finger 50 and front point of track relay 'I'R2 contact finger 5| and front point of the other track relay TR2 and the winding 43 of signal S2 This current of normal polarity causes the signal to display its green indication and to likewise cause all signals to the rear thereof, assuming'non-occupancy, to also display their green indications.

If we now assume that a vehicle occupies section 2 the energizing circuit for winding 43 is broken by one or the other or both-of the track relays TR2 whereby to cause the signal to display its red indication. Through contact finger 52 and back point of relay YGP2 current of reverse polarity is placed on the winding of the signal next-to the rear. This signal'thus displays its yellow indication and causes current of normal polarity to be placed on the control winding of the signal next in the rear thereof, whereby to cause it to display its green indication.

It should be noted that the pole changing of energy on the signal control winding at one location, by the signal at the location next in advance, is accomplished through a repeater relay as YGP2 and not by means of the contacts in the signal itself such as the contacts 44 and 45. If this pole changing function were handled by the contacts within the signal mechanism, with a signal of this construction, that is, an SA type signal, a signal which isdisplaying its yellow indication and is pole changed to display its green indication would necessarily in moving from yellow to green momentarily change the polarity on the signal next to the rear which is displaying the green indication to cause it to shift to its yellow indication and then back to its green indication. This shift would change the polarity on the signal next to the rear, etc., whereby there would be an undesirable momentary shift of'all of the clear signals through the red to the yellow and back again to the green upon every change in traffic conditions. By using the slow release yellowgreen repeater relay this faulty operation'is overcome but it is at the expense of employing a separate relay additional to the signal'itself when the SA type of signal is employed.

Considering more specifically the possible use of the signal contacts themselves for performing the pole changing function, we can assume that or normal polarity of current is applied to wire 48, and or reverse polarity of current is applied to the stop 55.

Now let us assume that a vehicle occupies a block so as to put the signal at its entrance at red with the next to the rear at yellow, and the next, etc., at green, and further, assume that the vehicle advances to the next block forward. It should be kept in mind that with the pole changing function carried by the signal contacts themselves, a signal at red places current of reverse polarity on the signal next to the rear to make it display yellow, and that a signal at yellow places current of normal polarity on the signal next to its rear to make it display green; and further, that the green signal also places current of normal polarity on the signal next to its rear, etc. When the train advances to the next block, the former red signal receives current of reverse polarity due to the signal next in advance having gone to red. Likewise, the former yellow signal receives current of normal polarity from the former red signal which is now yellow to produce a green indication. This last signal, passing from yellow to green due to current of normal polarity, must necessarily pass through the red indication stage, due to the construction of the signal andits spectacle in so doing places current of reverse polarity on the signal next to the rear. I

Thus, the first green signal, upon a train advancing a block, is first deenergized, thenis-energized with current of reverse polarity,'fand then is energized with current of normal polarity. Ac-

- arrow 8 cordingly, this signal not onlymust bridge a period of time when there is no energy on it but also a period of time when current of reverse polarity is on it, and accordingly, it will momentarily display a yellow indication and in thus passing from green to yellow will affect the green signal next in the rear thereof in the same manner.

From the above it can be seen that not only should the signal be slow to respond in order to bridge a period of time of deenergization but it must overcome a reversal in the polarity of the-current of energization, and thus this type of signal is not at all suited to carry the pole changing function by its own contacts. The yellow-greenrepeater relay, as described above, is slow to release and is always energized by current of the same polarity,-and,hence, the first green signal to the rear of the train, upon the train moving forward to the next block, not only does not have its-polarity of energization changed but does not have its energization interrupted since the yellow-green repeater relay holds up while the spectacle of the signal ahead moves from the yellow to the green position. Thus, the requirements for a properly operating system is a'relay of this type which not only is slow to release'and hence can bridge over agap of deenergization, but is so arranged that it is never reversely energized.

With reference to Fig. 4, the system here shown is'the same, in general, as that shown in Fig. 3 anddescribed above, except that the signal of the system of Fig. 3' is of the SA type and, as explained, requires a yellow-green repeater relay for pole changingthe-control circuit for the signal to the rear. In Fig. 4, the signal employed is of the polarized SC type, the same as disclosed and described with reference to Fig. 2, and with it no additional pole changing relay is required.

In Fig. 4 the stretch of single track is constituted by track rails 6 separated into track sections by insulating joints 1 with traffic being considered eastbound, i. e., in the direction of As described in reference to Fig. 4, the signal at each location is controlled through a line circuit extending to the signal next in advance and is either deenergized, energized with current of reverse polarity, or energized with current of normal polarity. For example, signal S2 at the entrance to sections 2 is controlled by signal S3 of the section next in advance through a line circuit including contact Bil, wire 6i, contacts 62 and 63 of track relays TR2 and the two control windings in signal S2 that is, the

red-yellow relay RYR and the yellow-green relay YGR.

With the signal arranged so that when current of negative or reverse polarity is applied to it, the red-yellow relay but not the yellow-green relay is energized, and when current of positive or normal polarity is applied both of these relays are energized, it can be seen that signal S4 at the entrance to the block occupied by the vehicle 64 is deenergized due to track relay EH4 being shunted out, and thus it displays its red indication.

The signal next to the rear is energized by cur-- rent of reverse polarity through contact finger 65 and back point of the red-yellow relay of the signal ahead to cause signal S3 to display its yellow indication. With signal S3 having its redyellow relay energized, current of normal polarity is applied to signal S2 to thereby cause it to display its green indication. The signals to the rear, assuming non-occupancy, all display green indications.

t can be noted that the red-yellow relay of each signal such as relay RYR of signal S2 is connected to be energized through a full-wave rectifier 66 whereby its energization is always in the same direction regardless of the polarity of current applied to the signal as a whole. Furthermore, due to the rectifier and also due to the inherent structure of this relay, it is slow to release.

Thus this red-yellow relay, which functions to move the spectacle of its signal, also has the unidirectional energization and the slow release characteristics of the yellow-green repeater relay such as relay YGP2 employed in connection with the type SA signal of Fig. 3. Accordingly, the pole changing function can be handled by the red-yellow relay of the type SC signal in addition to its other function of operating the spectacle and thus obviate any necessity or desirability for an additional yellow-green repeater relay as is absolutely essential when the type SA signal is employed.

In the system as shown in Fig. 4, upon the cation. It should be noted that signal S3 on having the polarity of the applied current changed from reverse to normal does not have the direction of energization of its red-yellow relay reversed, and hence the red-yellow relay of this signal S3 holds up during the momentary period of its deenergization while contact finger 65 of signal S4 moves from its back to its front point. Thus, the normal polarity of energization of the first signal displaying green to the rear of the vehicle, that is, signal S2 is not disturbed, and there is no possibility of any momentary tumble-down effect throughout the system.

Accordingly, the type SC signal can be employed in systems where formerly the type SA signal was employed, to manifest advantage since it obviates any necessity for any yellow-green repeater relay, as must be used in connection with the type SA signal.

In the various systems described above, it is of course to be understood that various modifications and refinements can be applied thereto if desired such as approach control means for the coding or for the energization of the light sources of the signals, or both, if desired. Furthermore, various coding means and various arrangements of track sections different from those shown, can be employed if desired. For example, the stretch of track between adjacent signals can include not only two track sections as shown in Figs. 3 and 4, but one only, if desired, or more than two, if desired.

The above rather specific description of several forms which this invention can assume is given solely by way of example, and is notintended in any manner whatsoever in a limiting sense. It is to be understood that various modifications, adaptations, and alterations may be applied to meet the requirements of practice without in any manner departing from the spirit or scope of this invention, except as clearly limited by the appended claims.

Having described my invention, I now claim:

1. In a wayside signaling system for railways, in combination, a stretch of track divided into electrically isolated blocks, a search light signal at the enerance end of each block, each signal including a spectacle movable progressively from a biased most restrictive position, through a lesser restrictive position, to a least restrictive position, a first and a second relay in the signal, means operatively connecting the relays to the spectacle so as to move the spectacle to its lesser restrictive position when the first relay is energized, and to move it to its least restrictive position when both relays are energized, means controlled by said first relay for placing energy of one or the other polarity on the exit end of the block next to the rear in accordance with traffic conditions, a polar neutral track relay associated with each signal, and means effective to energize said first relay when the associated track relay is energized with either polarity of current, and effective to energize said second relay only when the associated track relay is energized with current of one of said polarities.

2. In a wayside signaling system for railways, in combination, a stretch of track divided into electrically isolated blocks, a search light signal at the entrance end of each block, each signal including a spectacle movable progressively from a. biased most restrictive position, through a lesser restrictive position, to a least restrictive position, a first and a second relayin the signal, means operatively connecting the relays to the spectacle so'as to move the spectacle to its lesser restrictive position when the first relay is energized, and to move it to its least restrictive position when both relays are energized, means controlled by said first relay for placing energy of one 01' the other polarity on the exit end of the block next to the rear, a polar neutral track relay associated with each signal, magnetic means for retaining the neutral armature of the track relay in attracted position during change in polarity of energization of the relay, and means effective to energize said first relay when the track relay is energized with current of either polarity and effective to energize said second relay only when the polar relay is energized with current of a particular one of said polarities.

3. In a wayside signaling system for railways, in combination, a stretch of track divided into electrically isolated blocks, a search light signal at the entrance end of each block, each signal including a spectacle movable progressively from a biased most restrictive position, through a lesser restrictive position, to a least restrictive position, a first and a second relay in the signal, means operatively connecting the relays to the spectacle so as to move the spectacle to its lesser restrictive position only when the first relay is energized, and to move it to its least restrictive position only when both relays are energized, means polarizing said second relay so that it is responsive to current of one polarity only, rectifying means connecting the two relays in a common circuit in such manner that regardless of the polarity of current applied to the common circuit said first relay is energized by current flowing in a particular direction, means controlled by said first relay for placing energy of one or the other polarity on the exit end of the block next to the rear, and means for energizing said common circuit with current of a polarity varying with the polarity applied to the exit end of the associated block.

4. In a wayside signaling system for railways, in combination, a stretch of track divided into electrically isolated blocks, a search light signal a biased most'rest'rictive position, through a lesser restrictive position, to a least restrictive position,

a-first and a second relay in 't-he signaL' means i operatively connecting the relays to thespectacle so as to move the spectacle to its lesserrestrictive position when the first relay only is energized, and to move it to its least restrictive position when both relays are energized, means polarizing said second relay so as to be responsive to current of one polarity only, rectifying means connected with its input side to be energized in common with the second relay and its output side connected across the first relay so that the two relays are in a common circuit, means controlled by said first relay for placing energy of one or the other polarity on the exit end of the block next to the rear, a polar retained neutral relay connected across the entrance end of each block, and means controlled by the polar relay for energizing the common circuit with current of a polarity varying with the polarity applied to the polar relay.

5. In signaling systems for railways, in combination with a stretch of track separated into electrically isolated sections, a light signal at the entrance end of each section, each light signal including a spectacle movable from a biased, most restrictive postion, through an intermediate position, to a least restrictive position, two separate relays in the signal, means operatively connecting the relays to the spectacle so that the spectacle is moved to the intermediate position when one only of said relays is energized, and to the least restrictive position when both of said relays are energized, a pole changer operated by said one relay, means connected to said one relay to rectify all current energizing said one relay and control circuit means connecting the pole changer of each signal to the two relays of the signal next to the rear.

6. In combination With a railway track divided into sections by insulating joints, a track circuit for each section including a normally energized track relay, a search light signal at the entrance to one section and having two electro-magnets one of which is energizable only in response to current of one polarity and the other of which is energizable in response to current of either polarity, a line circuit extending along said one section, and energized by current of one or the other polarity in accordance with traffic conditions in advance, for controlling the electromagnets of said signal, said line circuit including a contact closed only if the track relay for said one section is energized, a second signal to the rear of said one signal, and a line circuit for energizing said second signal by current of one or the other polarity, and including pole changer contacts controlled by the said other electro-m-agnet of said search light signal.

7. In signaling systems for railways, in combination with a stretch of track separated into electrically isolated sections, a light signal at the entrance end of each section, each light signal including a spectacle movable from a biased, most restrictive, position, through an intermediate position, to a least restrictive position, two separate relays in each signal, means operatively connecting the two relays to the spectacle so that the spectacle is moved to the intermediate position when a particular one of said relays is energized, and to the least restrictive position only when both of said relays are energized, means --polarizing the other of said relays, of each sig- "nal, means connected to said one relay. in: each signal to render said one relay 'slow torelease I so as to'not release due tozchangexof polarity of energizing-current; and circuit means connecting 'each' signal with the signal next-to'thef rear and controlled by said one-relay of'eachysignal for I applying-energizing current'of one or the other ---polarity to "the twor'elays of thesignal'next to the-rear, in" accordance with tranic conditions ahead.

8. In signaling systems for railways, in combination with a stretch of track separated into a plurality of electrically isolated sections, a light signal at the entrance end of each section, each light signal including a spectacle movable from a biased, most restrictive, position, through an intermediate position, to a least restrictive position, two separate relays in each signal, means operatively connecting the two relays to the spectacle so that the spectacle is moved to the intermediate position when one of said relays is energized, and to the least restrictive position only when both of said relays are energized, means polarizing the other of said relays of each signal, means connected to said one relay of each signal to rectify all current applied to said one relay, and circuit means controlled by said one relay in each signal, in accordance with trainc conditions ahead, for applying current of one or the other polarity to the two relays of the signal next to the rear.

9. In a wayside signaling system for railways, in combination, a stretch of track divided into electrically isolated blocks, a search light signal at the entrance end of each block, each signal including a spectacle movable progressively from a biased, most restrictive, position, through a lesser restrictive position, to a least restrictive position, a first and a second relay in the signal, means operatively connecting the relays to the spectacle so as to move the spectacle to its lesser restrictive position only when the first relay is energized, and to move it to its least restrictive position only when both relays are energized, means polarizing said second relay so that it is responsive to current of one polarity only, rectifying means connecting the two relays in a common circuit, and means controlled by said first relay for causing energy of one or the other polarity to be applied to the common circuit of the signal next in the rear.

10. In signaling systems for railways, in combination with a stretch of track separated into electrically isolated sections, a light signal at the entrance end of each section, each light signal including a spectacle movable from a biased, most restrictive, position, through an intermediate position, to a least restrictive position, two separate relays in the signal, means operatively connecting the relays to the spectacle so that the spectacle is moved to the intermediate posi tion when one only of said relays is energized, and to the least restrictive position when both of said relays are energized, a pole changer operated by said one relay, means connected to said one relay to rectify all current energizing said one relay and control means operatively connecting the pole changer of each signal to the two relays of the signal next to the rear.

11. In a wayside signaling system for railways, in combination, a stretch of track divided into electrically isolated blocks, a search light signal at the entrance end of each block, each signal including a spectacle movable progressively from a spectacle so as to move the spectacle to its lesser restrictive position when the first relay only is energized, and to move it to its least restrictive position when both relays are energized, means polarizing said second relay so as to be responsive to current of one polarity only, rectifying 10 means connected with its input side to be energized in common with the second relay and its output side connected across the first relay so that the two relays are in a common circuit, and means controlled by said first relay and efiective to apply energy of one or the other polarity to the common circuit of the signal next to the rear.

OSCAR S. FIELD.

Images