US2152070A

US2152070A - Traffic signaling system

Info

Publication number: US2152070A
Application number: US190201A
Authority: US
Inventors: Logan Thomas Ashton
Original assignee: Associated Electric Laboratories Inc
Current assignee: Associated Electric Laboratories Inc
Priority date: 1938-02-12
Filing date: 1938-02-12
Publication date: 1939-03-28
Anticipated expiration: 1956-03-28

Description

March 28 1939. LOGAN 2,152,070

TRAFFIC S IGNALING SYSTEM vF'iled Feb. 12, 1938 0) IA! 2s. T 3 {I r 5 N N u u w m e i i1 2 u o: OVK 1 9 8 u .Q 0 Q 1 N o O v I I! fl v, INVENTOR. THOMAS ASHTON LOGAN MM,MM

ATTORNEYS Patented Mar. 28, 1939 UNITED STATES PATENT OFFlCE Associated Electric 11]., a corporation of Application February 12, 1938, Serial Claims.

The present invention relates to trafiic signaling systems, and more particularly to improvements in railway and highway traffic signaling systems, wherein a traflic signal device 5 located near an intersection of a'railway track and a highway is controlled by apparatus responsive to the condition of a stretch of railway track adjacent the intersection.

In signaling systems of the character noted, the trafiic signal device located near the intersection usually comprises two groups of traffic signals positioned to face the opposite highway approaches and two groups of traffic signals positioned to face the opposite railway approaches. Usually the group of traffic signals positioned to face each highway approach comprises clear, caution and danger signal lamps and the group of trafiic signals positioned to face each railway approach comprises caution and danger signal lamps; thereby presenting to the highway and the railway approaches universally recognized indications. The apparatus responsive to the condition of the stretch of railway track adjacent the intersection is so arranged that the traffic signal device is controlled to present trafiic signals to the highway and the railway approaches in a predetermined sequence as trains are moved with respect to this stretch of railway track.

In a signaling system of the type described it is desirable that the traffic signal device present traffic signals to the highway and the railway appreaches in the following sequence. Clear signals should be presented to the highway approaches and danger signals presented to the railway approaches when the stretch of railway track adjacent the intersection is clear of trains. Clear and caution signals should be presented to the highway approaches and danger signals presented to the railway approaches when a train enters this stretch of railway track. The caution signals presented to the highway approaches should be extinguished and danger signals presented to the highway approaches and caution signals presented to the railway approaches a predetermined time interval after the train enters this stretch of railway track. The danger signals presented to the highway approaches and the caution signals presented to the railway approaches should be extinguished and clear signals presented to the highway approaches and danger signals presented to the railway approaches after the train leaves this stretch of railway track provided the same is clear of other trains. It is extremely important that thetrafiic signal device Laboratories, Inc., Chicago,

Delaware presents traflic signals to the highway and the railway approaches in the sequence set forth above in order to prevent the presentation of confusing or erroneous indications to the highway approaches of the condition of the stretch of railway track adjacent the intersection. .While prior traffic signaling systems embodying apparatus responsive to the condition of a stretch of railway track adjacent a highway intersection for controlling the operation of a traffic signal device of this type in the manner described above are known, the apparatus involved is quite complicated in character and expensive to manufacture and install. Moreover, such apparatus is impositive in operation and must be frequently inspected and adjusted in order to control the traffic signal device to present the traffic signals to the highway and the railway approaches in the desired predetermined sequence.

It is an object of the present invention, therefore, to provide an improved traffic signaling system of the character briefly described above, which is of simple and economical construction, and which operates in a thoroughly reliable manner to present traffic signals to the highway and the railway approaches in the above-mentioned sequence.

It is another object of the invention to provide in a traffic signaling system of the character noted, improved and exceedingly simple apparatus which is controlled in accordance with the condition of the stretch of railway track adja cent the intersection and which is connected and arranged to control the traffic signal device in a manner such that it is impossible for the latter to present confusing traflic signals or depart from a predetermined sequence of presenting trams signals to the highway and the railway approaches.

It is a further and more specific object of the invention to provide a trafiic signaling system of the character described wherein improved and exceedingly simple circuit arrangements are employed for controlling the traffic signal device to present trafiic signals to the highway approaches in a predetermined sequence.

In general, the objects as set forth above are attained in accordance with the present invention by providing in a traflic signaling system of the character described, a control device operable between a normal position and an offnormal position, and apparatus whereby the control device positively controls the operation of the clear and danger highway signals and the caution and danger railway signals of the traffic signal device. The apparatus is so arranged that the clear highway signal and the danger railway signal are rendered active and the danger highway signal and the caution railway signal are rendered inactive, when the control device is operated to its normal position; and that the danger highway signal and the caution railway signal are rendered active and the clear highway signal and the danger railway signal are rendered inactive, when the control device is operated to its ofi-normal position. Also, this apparatus includes a timer, means operated when a train approaches the intersection for rendering the caution highway signal of the trafiic signal device active and for setting the timer into operation, control means operated by the timer for rendering the caution highway signal of the traffic signal device inactive and for operating the control device from its normal position to its offnormal position, and additional means for posi-- tively insuring that the caution highway signal of the traiiiic signal device is rendered inactive substantially simultaneously with the operation of the control device from its normal position to its off-normal position.

The novel features believed to be characteristic of the invention are set forth with particularity in the appended claims. The invention, both as to its organization and method of operation, together with further objects and advantages thereof, will best be understood by reference to the specification taken in connection with the accompanying drawing in which the single figure illustrates a trafiic signaling system having embodied therein the features of thepresent invention.

Referring now more particularly to the drawing, the traffic signaling system illustrated comprises a stretch of railway track l including track rails Ella and lb, along which traffic normally moves from the left toward the right as indicated by the arrow. The railway track i0 is intersected by a highway H, and a traffic signal device 62 is located at or near the intersection.

The traffic signal device 12 is provided with two sides I 2H positioned to face the opposite highway approaches and one side I 2R positioned to face the railway approach including the stretch of railway track l0. Although it is not essential, as it is assumed that trafiic normally moves in the direction indicated by the arrow from the left toward the right, it is preferable that the trafiic signal device l2 be provided with a side 52R positioned to face the opposite railway approach. Each side l2I-I of the trafiic signal device l2 carries a group of three signal lamps I3, I 4 and I5 arranged in vertical alignment, these lamps being green, amber and red, respectively, in order to present, when illuminated, corresponding clear, caution and danger signals to the highway approach. Each side [2R of the traific signal device It carries a group of two signal lamps I 6 and H arranged in vertical alignment, these lamps being amber and red, respectively, in order to present, when illuminated, corresponding caution and danger signals to the railway approach. The corresponding signal lamps of the corresponding groups are wired in multiple and -rovided with operating or energizing circuits adapted to be connected to a suitable source of A. G. supply. As shown in the diagrammatic layout illustrating one of the sides MR and one of the sides IZH of the traffic signal device 12, one terminal of each of the signal lamps I3 to El, inclusive, is connected to a common conductor C28] and the other terminal of each of these signal The common conductor C29 is connected directly to one side of a source of A. C. supply while the conductors C21, C23, C24 and C25 are connected to the stationary contacts R03 2, RG35, RG35 and RG37, respectively, of a control device or switch 3!. The switch 3! is provided with two armatures RASZ and RA33 which are operable together by a switch relay RSE from a normal position to an off-normal position. The armatures RA32 and RA33 are connected by way of a conductor C26 to the other side of the source of A. G. supply. In the switch St the armature RA32 controls the associated contacts RG34 and RG35, while the armature RA33 controls the associated contacts R036 and RG31. When the switch 3| is operated to its normal position, the energizing circuits of the signal lamps l3and ll are completed at the armature RA32 and its associated contact RG34 and at the armature RA33 and its associated contact RG37, respectively. The energizing circuit of the signal lamp it extends from one side of the source of A. G. supply by way of CW, the signal lamp i3, 02!, RG34, RA32 and C26 to the other side of the source of A. G. supply; and the energizing circuit of the signal lamp l1 extends from one side of the source of A. G. supply by way of C20, the signal lamp ll, G25, RG37, RA33 and C26 to the other side of the source of A. G. supply. With the switch 35 in its normal position, the energizing circuits of the signal lamps l5 and i5 are interrupted at the armature RA32 and its associated contact RG35 and at the armature RA33 and its associated contact RG36, respectively. When the switch 3i is operated to its offnormal position, the energizing circuits of the signal lamps i5 and i 6 are completed at the armature RA32 and its associated contact RG35 and at the armature RA33 and its associated contact RG36, respectively. The energizing circuit of the signal lamp i5 extends from one side of the source of A. G. supply by way of C26, the signal lamp l5, G23, RG35, RASZ and'GZB to the other side of the source of A. G. supply; and the energizing circuit of the signal lamp it extends from one side of the source of A. G. supply by way of C20, the signal lamp I6, 025, RG36, RA33 and C25 to the other side of the source of A. G. supply. With the switch 3'? in its ofi-normal position the energizing circuits of the signal lamps l3 and H are interrupted at the armature RA32 and its associated contact RG34 and at the armature RA33 and its associated contact RG31, respectively.

Thus the signal lamps l3, i5, i6 and H are controlled by the switch 3! in a manner such that when the clear highway signal lamp l3 and the danger railway signal lamp H are rendered active, the danger highway signal lamp !5 and the caution railway signal lamp it are rendered inactive; and that when the danger highway signal lamp l5 and the caution railway signal lamp F6 are rendered active, the clear highway signal lamp l3 and the danger railway signal lamp 1? are rendered inactive. This arrangement positively prevents the signal lamps controlled by the switch 3! from being operated to present confusing traffic signals to the highway and the railway approaches.

The ends of the track rails Mia and lfilb are separated from the ends of the adjoining rails by suitable insulated joints 9 in order to provide a track section its in the stretch of railway track it, the track section its being electrically insulated from the remainder of the railway track. The track section is is provided with a track circuit comprising a battery l8 and a track relay R40, the track relay R40 being normally energized from the battery 18 when the track section 108 is clear of trains, and being short-circuited and deenergized when the track section I08 is occupied by a train.

Apparatus responsive to the condition of the track section 60s for operating the traffic signal device I2 is provided, which includes the track relay R00; a slave relay R50; a vibratory or pendulum type relay R60, having a weighted armature RAG! adapted to vibrate for a predetermined time interval between two spaced-apart contacts RG62 and RG63 when the vibratory relay R60 is deenergized; a slow-to-release relay R10; and the switch relay R30. The slave relay R50 is provided with an energizing circuit extending from the positive terminal of a battery, not shown, by way of the armature RAM of the track relay R40 and the winding of R50 to the negative terminal of battery. The vibratory relay R60 is provided with an energizing circuit extending from the positive terminal of battery by way of the armature RA52 of the slave relay R50 and the winding of R60 to the negative terminal of battery. The slow-to-release relay R10 is provided with a primary energizing circuit extending from the positive terminal of battery by way of the armature RA5I of the slave relay R50 and the winding of R to the negative terminal of battery; and a secondary energizing circuit extending from the positive terminal of battery by way of the weighted armature RA6I of the vibratory relay R60, the associated contact RG62 or RG63, the armature RAH of the relay R10 and the winding of R10 to the negative terminal of battery. The switch relay R30 is provided with an energizing circuit extending from the positive terminal of battery by way of the armature RA12 of the slow-to-release relay R10 and the winding of R30 to the negative terminal of battery.

The caution highway signal lamp I4 is provided with an energizing circuit extending from one side of the source of A. 0. supply by way of C20, the signal lamp 14, C22, the armature RA13 of the slow-to-release relay R10, the armature RA53 of the slave relay R50 and a conductor G21, to the other side of the source of A. G. supply. Thus the energizing circuit of the caution highway signal lamp i0 is controlled by the slow-to-release relay R10 and the slave relay R50. The vibratory relay R60 and the slow-to-release relay R10 constitute atimer for controlling the operation of the trafiic signal device l2.

Considering the operation of the traffic signaling system illustrated, it-will be observed that the energizing circuit of the vibratory relay R60 and the primary energizing circuit of the slowto-release relay R10 are normally completed at RA52 and RAM, respectively, of the slave relay R50, which latter relay is controlled by the track relay R40. The secondary energizing circuit of the slow-to-release relay R10 is normally completed at RAM and the associated contact R862 of the vibratory relay R60 and at RA1I of the relay R10, thereby maintaining the switch relay R30 operated, which latter relay retains the switch 3! operated to its normal or operated position. When a train enters the track section 108, the winding of the track relay R40 is short-circuited or deenergized, causing the track relay Riii-to restore and interrupt at RAM the energizing circuit of the slave relay R50. The slave relay R50 then restores and interrupts at RA52 and RABI, respectively, the energizing circuit of the vibratory relay R60 and the primary energizing circuit of the slow-to-release relay R10. The vibratory relay R60 then releases its weighted armature RA6 I, which vibrates between the associated contacts RG62 and RG63, thereby intermittently completing and interrupting the secondary energizing circuit of the relay R10. The relay R10, being of the slow-to-release type, does not restore as long as its secondary energizing circuit is intermittently completed by the vibrating armature RAGE of the vibratory relay R60. However, after a predetermined time interval the armature RAGI of the vibratory relay R60 assumes an intermediate position between the associated contacts RG62 and RG63, thereby completely interrupting the secondary energizing circuit of the slow-to-release relay R10. Shortly thereafter, the slow-to-release relay R10 restores and interrupts at RA'H a further point in its secondary energizing circuit, and interrupts at RAlZ the energizing circuit of the switch relay R30. The latter relay then restores, thereby operating the switch 3! to its off-normal position. The time interval during which the secondary energizing circuit of the slow-to-release relay R10 is intermittently completed and interrupted depends upon the characteristic of the weighted armature RAB! of the vibratory relay R60, and may be varied between predetermined limits by adjusting the position of the weight carried by the armature RA6 I. Thus, the time interval between the time a train enters the track section I03 and the time the switch 3! is operated from its normal position to its oiT-normal position to control the trafiic signal device 12, may be conveniently adjusted within predetermined limits.

Also, it will be observed that when the slave relay R50 restores, upon the entrance of a train into the track section I05, it completes at RA53 the energizing circuit of the caution highway signal lamp 10 to render this signal lamp active.

The caution highway signal lamp It remains active until the slow-to-release relay R10 restores, a predetermined time interval after the train enters the track section I08, and interrupts at RA13 the energizing circuit of this signal lamp to render the same inactive. Furthermore, it will be seen that the caution highway signal lamp i4 is rendered inactive at substantially the same time the switch 31 is operated by the switch relay R30 from its normal position to its ofi-normal position to control the signal lamps i3, i5, i6 and I1 in the traflic signal device 12. This arrangement positively prevents the signal device 12 from presenting confusing traific signals to the highway and the rail- Way approaches.

Referring now more specifically to the operation of the traffic signaling system illustrated and assuming that the track section 10s is clear of trains, the above-traced energizing circuits of the track relay R40, the slave relay R50, the vibratory relay R00, the slow-to-release relay R10, and the switch relay R00 are completed and these relays are operated. Under this condition of the track section I0s, the energizing circuit of the caution highway signal lamp I0 is interrupted at RA53 of The traiiic signal device l2 thus presents clear trafiic signals to the opposite highway approaches and dangertraific signals to the opposite railway approaches. These traflic signals indicate to one using the highway that the stretch of railway track adjacent the intersection is clear of trains and that it is safe to enter the intersection.

When a train enters the track section ID, the track relay R40 is short-circuited and restores. Upon restoring, the track relay RM interrupts at RAM the energizing circuit of the slave relay R50. The latter relay then restores and interrupts at RAE! the primary energizing circuit of the slowto-release relay R16, and interrupts at RA -i2 the energizing circuit of the vibratory relay R69. Also, the slave relay R58 completes at RA53 the energizing circuit of the caution highway signal lamp I 4. At this time the traffic signal device 12 presents clear and caution traffic signals to the opposite highway approaches and danger signals to the opposite railway approaches. These trafiic signals indicate to one using the highway that a train has entered the stretch of track adjacent the intersection and that soon the train will enter the intersection. Also, these traffic signals indicate to the engineer that the traific signal device l2 has not operated to indicate to one using the highway that it is imminently dangerous to enter the intersection. When the vibratory relay Rfit is deenergized, the weighted armature RAM is released and begins to vibrate between the associated contacts R662 and RG53, thereby completing and interrupting intermittently the secondary energizing circuit of the slow-to-release relay R10 to retain the latter relay operated. After a predetermined time interval, depending upon the setting of the weighted armature RAM, weighted armature RAM assumes an intermediate position between the associated contacts R062 and RG63, thereby completely interrupting the secondary energizing circuit of the slow-to-release relay R70. A short time thereafter the slow-to-release relay R78 restores and interrupts at RAH a further point in its secondary energizing circuit. Also, the slow-to-release relay R78 interrupts at RATZ the energizing circuit of the switchrelay R30, and. interrupts at RA!!! the energizing circuit of the caution highway signal lamp M. The switch relay R3ll then restores, and substantially simultaneously the caution highway signal lamp i4 is extinguished. Upon restoring, the switch relay R30 causes the switch 3! to operate from its normal position to its off-normal position. When the switch 3! is operated from its normal position, it interrupts at RAM and the associated contact R036 the energizing circuit of the clear highway signal lamp I3, and interrupts at RASS and the associated contact RC3! the energizing circuit of the danger railway signal lamp l7. When the switch 3| is operated to its off-normal position, it completes at RA32 and the associated contact R035 the energizing circuit of the danger highway signal lamp l5, and completes at RA38 and the associated contact RG36 the energizing circuit of the caution railway signal lamp It. At this time the traiiic signal device l2 presents danger traffic signals to the opposite highway approaches and caution tramc signals to the opposite railway approaches. These traffic signals indicate to one using the highway that a train has entered the stretch of track adjacent the intersection and that it is imminently dangerous to enter the intersection. Also, these traific signals indicate to the engineer that the tralhc signal device if. has oper- ,ated to indicate to one using the highway that it is imminently dangerous to enter the intersection.

When the train leaves the track section lfis, the track relay R49 is energized, provided, of course,this track section is clear of other trains. The track relay R49 operates and. completes at RAM the energizing circuit of the slave relay R58. The latter relay operates and completes at RAM the primary energizing circuit of the slow-to-release relay R79, and completes at RA52 the energizing circuit of the vibratory relay R60. Also, the relay R50 interrupts at RA53 a point in the energizing circuit of the caution highway signal lamp M. The vibratory relay R60 operates and prepares at RAGI and the associated contact R062 a point in the secondary energizing circuit of the sloW-torelease relay Bill. The latter relay also operates and completes at RA'H its secondary energizing circuit, and completes at RA72 the energizing circuit of the switch relay R311. The slow-to-release relay R10 also prepares at RA13 a point in the energizing circuit of the caution highway signal lamp I4. Upon operating, the switch relay Rtll operates the switch 3| from its oiT-normal position back to its normal position. The switch 3|, upon operating from its oiT-normal position, interrupts at RA32 and the associated contact RG35 the energizing circuit of the danger highway signal lamp l5, and interrupts at RA33 and the associated contact R036 the energizing circuit of the caution railway signal lamp It. The switch 3!, upon operating to its normal position, completes at RA32 and the associated contact RG34 the energizing circuit of the clear highway signal lamp I3, and completes at RA33 and the associated contact RC3! the energizing circuit of the danger railway signal lamp ill. The trafiic signal device I2 then again presents clear traflic signals to the opposite highway approaches and danger trafiic signals to the opposite railway approaches. These traffic signals indicate to one using the highway that the stretch of railway track adjacent the intersection is again clear of trains and that it is safe to enter the intersection.

From the foregoing description of the traflic signaling system it Will be apparent that the signal device located near the intersection of the railway track and the highway is controlled by the apparatus responsive to the condition of the stretch of the railway track adjacent the intersection in a simple manner to present trafiic signals to the highway and railway approaches in a predetermined sequence. Moreover, the control apparatus is so arranged that it is impossible for the signal device to present confusing trafiic signals to these approaches or depart from the predetermined sequence of presenting trafiic signals.

While there has been described what is at present considered to be the preferred embodiment of the invention, it will be understood that various modifications may be made therein without departing from the invention, and it is intended in the appended claims to cover all such modifications as fall within the true spirit and scope'of the invention.

What is claimed is:

1. A traffic signaling system comprising a stretch of railway track intersected by a highway, clear and caution and danger signals located near the intersection, a device operable between a first position and a second position, apparatus whereby said device controls the operation of said clear and said danger signals, said apparatus being so arranged that said clear signal is rendered active and said danger signal is rendered inactive when said device is operated to said first position and said danger signal is rendered active and said clear signal is rendered inactive when said device is operated to said second position, a timer, means operated when a train approaches the intersection for rendering said caution signal active and for setting said timer into operation, and means controlled by said timer for rendering said caution signal inactive and for causing said device tooperate from said first position to said second position.

2. A traific signaling system comprising a stretch of railway track intersected by a highway, clear and caution and danger signals located near the intersection, a device operable between a normal position and an off-normal position, apparatus whereby said device controls the operation of said clear and said danger signals, said apparatus being so arranged that said clear signal is rendered active and said danger signal is rendered inactive when said device is operated to its normal position and said danger signal is rendered active and said clear signal is rendered inactive when said device is operated to its off-normal position, means including a relay foroperating said device, means operated when a train approaches the intersection for rendering said caution signal active and for conditioning said relay to operate after a predetermined time interval, and means responsive to the operation of said relay for rendering said caution signal inactive and for causing said device to operate from its normal position to its cit-normal position.

3. A trafl'lc signaling system comprising a stretch of railway track intersected by a highway, clear and caution and danger signals located near the intersection, a device operable betweena normal position and an off-normal position, apparatus whereby said device controls the operation of said clear and said danger signals, said apparatus being so arranged that said clear signal is rendered active and said danger signal is rendered inactive when said device is operated to'its normal position and said danger signal is rendered active and said clear signal is rendered inactive when said device is operated to its oiinormal position, means including a slow-to-release relay for operating said device, an energizing circuit for said slow-to-release relay, means operated when a train approaches the intersection for rendering said caution signal active and for interrupting the energizing circuit of said slow-to-release relay, and means responsive to the restoration of said slow-to-release relay for rendering said caution signal inactive and for causing said device to operate from its normal position to its off-normal position.

4. A trafilc signaling system comprising a stretch of railway track intersected by a highway, clear and caution and danger signals located near the intersection, a device operable between a normal position and an off-normal position, apparatus whereby said device controls the operation of said clear and said paratus being so arranged that said clear signal is rendered active and said danger signal is rendered inactive when said device is operated to its normal position and said danger signal is rendered active and said clear signal is rendered inactive when said device is operated to its off-normal position, means including a slow-to-release danger signals, said aprendering said caution signal inactive and for causing said device to operate from its normal position to its ofi-normal position,

5. A traffic signaling system comprising a stretch of railway track intersected by a highway clear and caution and danger signals located near the intersection, operating circuits for said signals, means including a switch operable between a first position and a second position for controlling the operating circuits of said clear and said danger-signals, said switch being so connected and arranged that said clear signal is rendered active and said danger signal is rendered inactive when said switch is operated to said first position and said danger signal is rendered active and said clear signal is rendered inactive when said switch is operated to said second position, a timer, means operated when a train approaches the intersection for rendering said caution signal active and for setting said timer into operation, and means controlled by said timer for rendering said caution signal inactive and for causing said switch to operate from said first position to said second position.

6. A a trafiic signaling system comprising a stretch of railway track-intersected by a highway, clear and caution and danger signals located near the intersection, circuits for energizing said signals, means including a switch operable between a normal position and an off-normal position for controlling the energizing circuits of said clear and said danger signals, said switch being connected and arranged to complete the energizing circuit of said clear signal and to interrupt the energizing circuit of said danger signal when said switch is operated to its normal position and to complete the energizing circuit of said danger signal and to interrupt the energizing circuit oi said clear signal when said switch is operated to its off-normal position, a timer, means oper-' ated when a train approaches the intersection for completing the energizing circuit of said caution signal and for setting, said timer into operation, and means controlled by said timer for interrupting the energizing circuit of said caution signal and for causing said switch to operate from its normal position to its off-normal position.

7. A trafiic signaling system comprising a stretch of railway track intersected by a highway, clear and caution and danger highway signals located near the intersection, caution and danger railway signals located near the intersection, a device operable between a first position and a second position, apparatus whereby said device controls the operation of said clear and said danger highway signals and said caution and said danger railway signals, said apparatus being so arranged that said clear highway signal and said danger railway signal are rendered active and said danger highway signal and said caution railway signal are rendered inactive when said device is operated to said first position and said danger highway signal and said caution railway signal are rendered active and said clear highway signal and said danger railway signal are rendered inactive when said device is operated to said second position, a timer, means operated. when a train approaches the intersection for rendering said caution highway signal active and for setting said timer into operation, and means controlled by said timer for rendering said caution highway signal inactive and for causing said device to operate from said first position to said second position.

8. A traflic signaling system comprising a stretch of railway track intersected by a highway, clear and caution and danger signals located near the intersection, a device operable between a normal position and an off-normal position, apparatus whereby said device controls the operation of said clear and said danger signals, said apparatus being so arranged that said clear signal is rendered active and said danger signal is rendered inactive when said device is operated to its normal position and said danger signal is rendered active and said clear signal is rendered inactive when said device is operated to its off-normal position, means including a slow-to-release relay for causing the operation of said device to its normal position, primary and secondary circuits for energizing said slow-to-release relay, a vibratory relay having an armature adapted to vibrate for a predetermined time interval after it is set into operation, means operated when a train approaches the intersection for rendering said caution signal active for interrupting the primary energizing circuit of said slo-w-to-release relay and for controlling the operation of said vibratory relay to set said armature into operation, means including contacts controlled by the vibration of said armature for intermittently completing the secondary energizing circuit of said slow-to-release relay during a predetermined time interval, thereby to retain said slow-to-release relay operated during said predetermined time interval, and means responsive to the restoration of said slowto-release relay for rendering said caution signal inactive and for causing said device to operate from its normal position to its oil-normal position.

9. A traffic signaling system comprising a stretch of railway track intersected by a highway, clear and caution and danger signals located near the intersection, a device operable between a normal position and an off-normal position, apparatus whereby said device controls the operation of said clear and said danger signals, said apparatus being so arranged that said clear signal is rendered active and said danger signal is rendered inactive when said device is operated to its normal position and said danger signal is rendered active and said clear signal is rendered inactive when said device is operated to its oir-normal position, a timer, means operated when a train enters said stretch of railway track for rendering said caution signal active and for setting said timer into operation, means including a relay for controlling the operation of said device, a circuit for energizing said relay, and means operated by said timer for rendering said caution signal inactive and for controlling the energizing circuit of said relay to cause said device to operate from its normal position to its offnormal position, said last-mentioned means being operated when the train leaves said stretch of track to control the energizing circuit of said relay to cause said device to operate from its off-normal position back to its normal position. 10. A trafiic signaling system comprising a stretch of railway track intersected by a highway, clear and caution and danger signals located near the intersection, a device operable between a normal position and an off-normal position, apparatus whereby said device controls the operation of said clear and said danger signals, said apparatus being so arranged that said clear signal is rendered active and said danger signal is rendered inactive when said deviceis operated to its normal position and said danger signal rendered active and said clear signal is rendered inactive when said device is operated to its olfnormal position, a timer, means operated when a train enters said stretch of railway track for rendering said caution signal active and for setting said timer in-to operation, and control means operated by said timer for rendering said caution signal inactive and for causing said device to operate from its normal position to its oilnormal position, said first-mentioned means being operated when the train leaves said stretch of railway track for reconditioning said timer for operation, said control means being operated when said timer is reconditioned to cause said device. to operate from its oiT-normal position back to its normal position.

THOMAS ASHTON LOGAN.