US1531834A - Railway-traffic-controlling apparatus - Google Patents

Description

March 3'1. l925.

Amplifier G. W. BAUGHMAN RAILWAY TRAFFIC CONTROLLING APPARATUS Filed Oct. 10, 1924 |NVENTOR f F5 1 ATTORNEY Patented Mar. 31, 1925.

UNITED STATES I 1,531,834 PATENT OFFICE.

GEORGE W. BAUGHMAN, O'F EDGEWOOD BORQUGH, PENNSYLVANIA, ASSIGNDR TO THE UNION SWITCH & SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A CORPO- RATION OF PENNSYLVANIA.

RAILWAY-TRAFFIC-CONTROLLING APPARATUS.

Application filed Qctober 10, 1924. Serial No. 742,841.

To all whom it may concern:

Be it known that I, GEORGE lV. BAUGH- MAN, a citizen of the United States, residing at Edgewood Borough, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improve-- ments in Railwayllraffic-Controlling Apparatus, of which the following is a specification. I

My invention relates to railway trafiic controlling apparatus, and particularlyio apparatus of the type comprising train carried governing apparatus controlled by energy received from the .trackway. More specifically, my present invention relates to the trackway portion of'such apparatus.

I will describe one form of apparatus embodying my invention, and will then .point out the hotel features thereof in claims.

The accompanying drawing is a diagrammatic view showing one form of railway traflic controlling apparatus embodying my invention.

Referring to the drawing, the reference characters 1 and 1 designate the track rails of a stretch of railway track. These rails are divided, by means of insulated joints 2, into a plurality of tracksections, of which only one section, AB, is shown in the drawmg. 7 Each track section is provided with a source of track circuit current, here shown as a track transformer designated by thereference character T with an exponent corresponding to the location and having a secondary winding 5 connected across the rails adjacent the right hand end of the section. An impedance 6, here shown as a reactor, is interposed between the secondary 5 of each track transformer T and one rail 1 of the associated section. The primary *1- of each track transformer is constantly supplied with alternating current from a suitable source such as an alternator Mover line wires 3 and 3".

Each section is further provided with a track relay designated by the reference character R with an appropriate exponent .and connected across the rails adjacent the left hand end of the associated section. These relays may be used to control traffic governing means not shown in the drawing in any desired manner.

Means are also provided for supplying section AB with a loop current which flows through the rails of the section in parallel. For this. purpose I connect an impedance 11 across the rails adjacent the left hand end of the section and a similar impedance 12 across the rails adjacent the right hand end of the section. As here shown the opposition offered by impedances 11 and 12 is largely due to their ohmic resistance. The immediate source of loop current for this section is a loop transformer L having the terminals of its second ary 9 connected with the mid points of impedances 11 and 12. The primary 8 of transformer L is supplied with alternating cur rent from line wires 3 and 3", over a'front contact 7 of track relay' R It follows that when relay B is energized, that is, when the section to the right of point B is unoccupied, section A-B is supplied with loop current.

The section to the left of point A is occupied by a train indicated diagrammatically at V. Located in-front of the forward axle of this train are two magnetizable cores 16 and 16 provided with windings 17 and 17*, respectively. and one located in inductive relation witheach track rail. VVindings 17 and 17 are connected in series in such manner that the voltages induced therein by alternating currents flowing inopposite directions in the two track rails at an instant are additive. The two windings 17 and 17 deliver current to winding 18 of an induction motor relay K. Located at some other convenient place on the train, such-as in rear ofthefirst axle, aretwo other cores 19 and19 carrying windings20 and 20 respectively and one locatedin inductive relation with each track rail;v The two windings 20 and 20 are connected in series in such manner that voltages induced therein by alternating currents flowing in the same direction in the two track rails at an instant; are additive and these "windings-serve to supply current to winding 21 of relay K. Suitable amplifyingapparatus '25 may be interposed between each winding of relay K and the receiving apparatus on the train.

In addition to the two windings 21 and 18, relay K comprises a rotor 22 and a contact. system comprising a contact 23 controlled thereby. This relaynmay be used to control train governing apparatus not shown in the drawing, in any desired manner. When that this optimum phase relation is 90. The

torque of a relay of this type increases with increases in the sine of the phase angle and also, of course, with increases in the current through either winding.

It will be seen that the track circuit current traverses a reactor 6 whereas the loop current traverses resistances 11 and 12 which are substantially non-inductive, and as a result the loop current and the track circuit currents would ordinarily be displaced in phase substantially 90.

I have found, however, that in long track sections a portion of the loop current leaks away from the rails at one end of the sec tion, traverses the ground instead of'the rails, and returns to the rails at the other end of the section. As a result the magnitude of the loop current near the center of the section is considerably smaller than adj'a'cent the ends of the section, and, moreover, the loop current near the center of the section lags behind the loop circuit voltage by a considerable amount. The phase angle between the loop and track circuit currents I is therefore diminished and the operation of the relay K is rendered less reliable.

To overcome this undesirable condition I connect an impedance comprising two reactors 10 and 10 in series across the rails adjacent the left hand end of the section and connect the left hand terminal of primary 8 of loop transformer L with the common point a? of these reactors. I also connect the right hand terminals of primary 8 and secondary 9 together. By properly proportioning the reactors 10 and 10 the loop current may be made to lead the loop volt I age and thereby to counteract the lag caused by leakage through the ground.

The parts are so proportioned that the optimum phase relatlon between the loop" and track circuit currents is obtained near the center of the section. At the ends of the section, then, the loop current will lead the applied voltage, and the track circuit current will lag behind the applied voltage by. approximately 90. The phase angle will, then, at the ends of the section, be less desirable than the optimum, but at the ends of the track section the loss due toleakage through ground is a minimum and the magnitude of the current 1n the rails at those points is sufiicient to insure reliable operation of the relay.

It follows that with my invention the operation of the relay is more reliable, and that safety of operation may be insured with less power, than would be the case were the loop current not shifted to lead the voltage. I

Although I have herein shown and described only one form of railway traffic controlling apparatus 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 stretch of railway track, a transformer, a loop circuit including the rails of the stretch'in parallel and the secondary of said transformer, means for supplying energy to the primary of said transformer, and means for connecting one terminal of said primary with one terminal of the secondary and for connecting the re maining terminal of said primary with the rails of said stretch.

2. In combination, a stretch of railway track, a transformer having a primary and a secondary, means for supplying said primary with alternating current, and means for supplying current to the rails of the stretch in parallel from said primary and from said secondary.

8. In combination, a stretch of railway track, a transformer having a primary and a secondary winding, means for connecting one terminal of each of said winding with the rails of the stretch, means'including an impedance for connecting the free terminal of said primary winding with the rails, and means including a secondimpedance having a power factor different from the power factor of said first impedance for connecting the free terminal of the secondary winding with the rails of the stretch.

4. In combination, a stretch of railway track, a transformer having a primary and a secondary winding, a first impedance connected across the rails adjacent one end of the stretch, a second and a third impedance connected across the rails adjacent the other end of the stretch, means for connecting one terminal of each winding of said transformer with the said first impedance, and means for connecting the free terminals of said primary and secondary windings with said second and third impedances, respectively. i

5. In combination, a section of railway track, a source of alternating electromotive force, means for supplying to the section a track circuit current which .lags such electromotive force by substantially 90, means for supplying the rails of the section with loop current Which leads said electromotive force at the ends of the section, but the magnitude of which loop current is diminished and the lead of Which loop current With respect to said electromotive force is decreased near the center of the section, due to leakage of current through the ground, and train carried governing means including a relay having a torque which increases With increase in the magnitude of either track circuit current or loop current and also with increase in sine of the phase angle between said currents.

6. In combination, a stretch of railway said transformer With the rails of the stretch, a resistor connected across the rails of the stretch and having its mid point con nected with the free terminal of said secondary, and two reactors connected in series across the rails of the stretch and having their common point connected With the free terminal of said primary.

In testimony whereof I aflix my signature.

GEORGE W. BAUGHMAN.

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