US1705611A - Railway signaling system - Google Patents

Description

March 19, 1929. R. M. GlLsON RAILWAY VSIGNLING SYSTEM Filed April 17, 192

' sections C-D, D-E, etc.

the arrow.

Patented Mar. 19, 1929.

ROBERT M. erLsoN, or PITTSBURGH, PENNsYnVANrA, Assrenon To'. Tian Union SWITCH a steam. COMPANY, or sWrssvaLE, PENNSYLVANIA, ir coarse-africa or PENNSYLVANIA.

v RAILWAY SIGNALING SYSTEM.

appiaaaonaieaapra17,1928, serial no. 270,59?.

My invention relates to railway signaling systems, and particularly to systems lof the type involving polarized line circuits for the control of three-indication signals.

' I will .describe one form of system einbodying my invention, and will then point out the novel features thereof in a claim.

` The accompanying drawing is a diagrammatic view showing one form of system embodying Vmy invention.,

Referring to the drawing, the reference characters l and l@ designate the track rails of a railway track along which traic nor-A mally moves in the direction indicated by l These rails are divided by insulated joints 2 to form a pluralityof track Each section is provided with a track circuit comprising a source of current 12 connected across the rails at the exit end of the section, and a track relay connected across the rails at the entrance end of the section, each track relay being designated by the referencecharacter T with a suitable exponent corresponding to the location. Y i

"Associated with each track sectionvis -a polarized line relay designated by the reference character L with an exponent corresponding to theflocation, and also .associated with each track section is a slow-releasing relay designated by the reference character A with anV exponent corresponding to the location. The line relay L for each section is controlled by the track relay for the same section and by pole-changing contacts on the slow-releasing.relay A for the section next iin advance. For example, tbecireuit for lineV relay LC is from terminal B of a 'suitable source of current, through 1 front Contact 4- of traekrelay TD, front point'of contact Sfof relay AD, frontcontaet 3 of track relayTD,` 'winding ofl relay'LD, and front point of Contact 9 of relay AD, to terminal O of the same sourceof current. The current which is then supplied tov relayLC is of what l will term normal polarity, so hat relay LD is then energized in the normal direction, wherein its normal contact 6 6@ is closed. When relay AD is open, but track relay TC is closed, the circuit for relay LC is from terminal B, through the back pointv of contact- 9 of relay AD, winding of relay LC, contact 3 of track relay TD, and theback e across contact 4.

includes merely the back point enters section C-eD. This trainopens tra.;

point ofcontact 8 of relay ADto terminal The current'then supplied to relayLC is of reverse polarity, so that the reverse vcontact (i--Gb of this relay -is closed. n It. will be noted that the eircuitglast tracedfor rel ayLD does not include the front contact 4t of track relay TD. The reason for this will be 'explained hereinafter, as 'well as the reason for the resistance -10 which .is connected Each relay A is provided with a circuit which includes frontcontact 5 of the associ-l -ated line relay L, which circuit will `beiobvious from the drawing. K It follows, that each relay A is energizedwhenever the vas-l sociated relay L is cle-energized.

Each traeksection is provided `with a'sig nal designatedby the reference characterxS with an exponent corresponding to the loca p tion. Each of these signals comprises a pre-- ceed lamp G, a Ycaution lamp Y,and av stop lamp R. Referring to signal SD, for ei;- ample, .the lcircuit for the'procecd lamp (il is from terminal B, throughfront point of contact 7 of the slow'releasing relay AD, nor'- mal contactA 6 6a kof relay LC, and lamp G to terminal O. Theeircuit for the caution lamp includes front point of-centact '7 of relay'ACand thefrerverse'contact v(SK-(3" of rclay LC. The circuit for the stop lamp 'R of contact 7 of relay AC.

The operation ofthe system Ais as follows: .Vf

When rthe parts are not intluenced by the presencev of trains, each relay L is ener-"' gized V'in Vthe normal direction, so .that all signals S yindicate proceed.l I vwill new sume that a train' I'novingl toward the r C relay TC, lthereby denergizing relay L, which in turn denergizes relay AC, with the result that signalV Sechanges tothe stopl indication. As the train enters section'l-E, it deenergizes relays TD, LD and AD, so that signal SD. changes to the stop indication.

The pole-changingcontacts Sand 9 of relay AD are now reversed, so that as. soon as track relay TC becomesenergized, relay LC will become energized in the reverse direction, with the result that signal SD' will changeto the caution indication? After the 65* train leaves section D-E, relays LD and AD Will become energized, so that-'relay LC will the proceed lamp G of signal SD.

then be energized in the normal direction,

and signal SD will again give the proceed indication. l v Q The foregoing explanation of the opera tion of thesystein contains no mention ofv the track relay contacts 4. The reason for tliesecontacts, is as follows: Assuming that the circuit for relay LC does not include contact 4 of track relay TD, then when a light engine passes point D at high speed, track relay TC might become closed before the front contacts vof relay AD become opened.'Y Relay LC would then be energized in the .normal direction for a brief interval of time, with the result that proceed l'anip G of' signal SD might be momentarily lighted, so that this signal would 'momentarily give the proceedindication. As soon as such light engine enters section D-E, however, Contact 4 of track relay TD will open before contact 3 of track relay TC will close, with the result that the normal circuit for relay LD is held open during-the interval between the opening of relay TD and the opening of tliefront contacts of slowr -ileas-4 l-E from the venitv end, or if a switch inr this section shouldlie opened., the opening of Contact 4 of relay TD would open the normal circuit for relay LD before Vthe reverse circuit would become closed attlie back contacts of relay AD, with the result vthat relay Y LC would be: cle-energized, and the interval during' 'which this relayy is Lie-energized might be vsufficient to-'permit the contacts of relay AD to release, with the result that .signal SD might* momentarily vgive a stop indication before changing to the caution indication. To avoid this possibility, l have ,connected al resistance l0 across the contact 4 of each track relay, and the parts areso adjusted that when line relay LC, 'for eX- ample, is closed, it will remain closed withV contact 4 open, provided, of course, that the circuit for relay LC is closed at all other points. If relay LD 'is open, however, v it will notV close in' resp-onse tothe current which it receives through the resistance 10 when contact 4 is open. In other words, considering the normal circuit only relay LC, the parts are 'so adjusted that the current received by relay LC when contact 4 is open, is greater than the releasevalue of this relay but less than the pick-up value,

'wliereas, when contact 4 is closed the cur- Vrent received by relay LC is. greater than its pick-up value. Assuming now thata train backs into section D--E, contact 4 of track relay TD will open, but sufficient current will be supplied yto relay LD through resistance-10 to keep this relay energized, Awith the result that no vchange will occur in so fai' as relay LC is concerned until relay AD releases, whereupon, relay LC will become energized in the reverse direction and signal SD will change from the proceed indication to the caution indication.v

Although l have herein shown and described only oiie form of system embodying my iiivention,.it is understood that various changes and .modifications may be made therein within the scope ofthe appended claim without departing from the spirit and scope of my invention.

Having thus described niy invention, what l claim is:

ln combination, a strctch'of railway track divided into sections, a track circuit including a track relay foreach section, a polare ized line relay for each section, Ya slow-releasing relay for each` section controlled bythe associated line relay, a cii'cuiti'for each line relay -including a front contact of 'the track relay for the associated ysection and pole changing contacts of theslowfor releasing relay for the section -neXtiin advance, each line relay vcircuit including a vfront contact of the track relay forthe section next in advance'whichV contact is interposed between the source ofl current and one ofthe pole changingrcontacts in such circuit', each line relay Vcircuit alsoV including a resistance kconnected acrossthe last-mentioned track relay contact, the parts of each line rclayfcircuit being so proportioned ,that when the vlast-mentioned trackl relay Contact is open and the circuit is otherwise closed, the line relay will remain'V closed if it is alread f closed but will not close if it is open, and signals for the sec` tions controlled by said line relays' and slow-releasing relays. I In testimony whereof I affix my signature,

' ROBERT M. GILSON.

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