US 3432653 A
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Description (OCR text may contain errors)
March 11, 1969 F. H. WINKS ET 3,432,653
SELF-ADJUSTING TRACK CIRCUITS Filed July 14. 1966 I0 I a A '8 II Af+ l5 I I v u l l PRIOR ART k FIG. 1
RELAY 22 I5 L 3 I f j I J FIG. 2 INVENTORS FRED H. wmxs HENRY e. WANSER ATTORNEY United States Patent 2 Claims ABSTRACT OF THE DISCLOSURE Our invention relates to track circuits and more specifically to a self-adjusting track circuit which will compensate for track current losses due to moisture causing a current leakage or current seepage from rail to rail.
The track circuits in use in railroading are extremely important and delicate devices that control the movement of trains, provide for time schedules and protect the lives of the passengers. The failure of even one signal can cause either a stoppage of the train or a serious accident. Present day track signal circuits have been perfected to function well under normal conditions but these same circuits are unable to cope with the adverse conditions of moisture in the trackway. These adverse conditions can substantially prevent the power supply from ever reaching the signal controlling relay. In fact, a substantial loss of current seepage across the tracks is the equivalent of a train axle on the tracks and causes the relay to function as if a train were actually on the rails. In addition, even though the power source or supply may not be completely shunted, enough moisture may be present to cause a current leakage or seepage which will drain the power supply to the point where it could not function properly on the relay.
It is necessary during adverse moisture conditions to adjust the elements of the track circuit to compensate for current seepage loss and then during dry conditions to readjust the elements for normal usage. Thus costly manhours of labor are consumed in providing and keeping the track circuits in proper operating conditions.
Therefore an object of the present invention is to form a track circuit which is self-adjusting to all moisture and weather conditions so as to provide a substantially cOnstant supply of electric power to the track relay.
A further object is to provide a track circuit with a means for compensating for the loss of current due to seepage across the rails so that the correct amount of current is provided to the relay so that it can function properly.
Another object is to provide a track circuit with an additional automatic variable source of electric current which supplies substantially the same amount of current to the track relay as is lost by current leakage or seepage across the rails with the track section unoccupied.
We accomplish these and other objects by providing in the track circuit an additional source of current, one terminal of which is connected to one track rail and the other terminal to an electric conductor, either a wire, cable, strip or piece of rail and placing the wire, cable, strip or piece of rail between and approximately parallel to the track rails, and having the additional source of current in the same phase as the main source of current so that if moisture in the trackway shunts out the main current, the same moisture will cause the current in the wire, cable, strip or piece of rail to pass to the other rail, thus establishing a secondary source of power and providing current to compensate for the current seepage loss in the primary circuit.
For further comprehension of the invention and of the 3,432,653 Patented Mar. 11, 1969 objects and advantages thereof, reference will be had to the following description, the accompanying drawing and to the appended claims in which the various novel features of the invention are more particularly set forth.
In the drawing, FIG. 1 is a schematic sketch of a normal present day track relay circuit and FIG. 2 is a similar type sketch of the circuit shown in FIG. 1, but with the additional elements and circuit providing leakage and seepage protection.
In the drawing and in the specification, in which like numerals indicate similar elements, the present day track circuit 10 -(see FIG. 1) is shown comprised of a circuit section A having a power source 11, resistance 12 and fuse 13 connected in series, as shown, to track rails 14 and 15. It should be noted that rail 15 is insulated and is not electrically continuous while track rail 14 is electrically continuous. Also a part of section A and connected in series to track rails 14 and 15 is a fuse 16, a resistance 17 and one coil 18 of a transformer. The track circuit 10 is also provided with circuit section B, which is comprised of the other coil 19 of the transformer, a power source 20 and a signal operating relay 21, all connected in series. As is normal, the power source 20 is much smaller than and of an opposing polarity to the power source 11. Thus normally, the power source 11 prevails over the power source 20 and holds the relay in a position showing a clear track. However, when a train axle is across the rails, it acts as a shunt to the power source 11 and power source 20 then functions on the relay 21 and causes it to move the signal to a position which indicates a train is on the track.
As all the elements heretofore shown and numbered in FIG. 1 are again shown in FIG. 2, they need not be repeated and their existence will be assumed in FIG. 2. The new elements (see FIG. 2) that provide protection against current leakage and current seepage loss comprise an open circuit C extending from track 15 through a fuse 22, a resistance 23 and a power source 24, all in series, to the end of a wire, cable, strip, piece of rail or other elongated conductor 25. The conductor 25 is positioned between the rails 14 and 15 with its elongated axis aligned with the rails 14 and 15 and is of substantial length to allow ample leakage or seepage of current across to rails 14 and 15. In fact, should physical conditions warrant conductor 25 could be as long as rail 15. Conductor 25 should not be insulated and should be positioned along the roadbed in an exposed manner so that moisture which can cause electrical seepage from one rail to the other of the current from power source 11 will equally well cause a current from power source 24 to pass from conductor 25 across to rails 14 and 15. The power source 24 is in phase with the power source 11 and must be large enough to completely take over the function of source 11 when necessitated by trackway conditions. For best results circuit C should be joined to circuit section A in the vicinity of rail 15 and fuse 13, as is shown in the drawing (FIG. 2).
Although we have shown the invention in only its main form it should be understood that other combinations of electrical units not shown or described may be used to form circuits different from that herein disclosed but which circuits will embody the basic principles and ideas herein set forth. Therefore, we do not wish to limit ourselves to the precise circuit herein disclosed, and we therefore reserve the right to all changes and modifications of the invention coming within the scope of the invention.
Having thus described our invention, what we claim as new and desire to secure by United States Letters Patent is:
1. In a track circuit for vehicles having dominating AC power source and a pair of track rails capable of acting as conductors to form a main circuit, an additional AC power source and a noninsulated conductor, said additional AC power source being in phase with the first AC power source and connected to one rail and to the conductor and the conductor being positioned between the rails, said additional AC power source adding to the total power available to cause the power to remain approximately constant irrespective of the seepage loss across the track, a. signal circuit having a third AC power source of subordinate character connected to said main circuit through a transformer whereby the signal will be operative only when the main circuit is completely shunted by an axle of a vehicle.
2. A track circuit as defined in claim 1, and said conductor being of an elongated shape and substantially parallel with the rails, and being electrically insulated at its ends and said additional power source being connected to said insulated rail.
References Cited UNITED STATES PATENTS 1,687,124 10/1928 Gilson.
2,089,836 8/1937 Martin.
FOREIGN PATENTS 289,537 4/ 1928 Great Britain.
DRAYTON E. HOFFMAN, Primary Examiner.