Not Applicable.
1. Field of the Invention
The present invention relates to a method of improving shunt detection on railroad tracks and to a railroad highway crossing signal electronic assembly, and more particularly, but not by way of limitation, to a railroad highway crossing signal electronic assembly that improves train detection on rails with poor shunting conditions.
2. Description of the Related Art
Grade-crossing signals and gate arms can be actuated by a variety of track circuits. A traditional relay circuit has often been used for grade-crossing signals and gate arms.
When the circuit detects the presence of a train, it actuates circuits that cause grade-crossing signals to begin flashing and cause gates to be lowered if train exists in the crossing.
Grade crossing predictor circuits are able to determine a distance from the train to the crossing and can determine whether the train is approaching the crossing or moving away from the crossing. This ability allows a controller to activate a warning system with a warning time prior to the train reaching the crossing.
Some prior circuits employ tuned shunts at either end of an approach area to a crossing and work by transmitting a signal through the rails and shunts and sensing an inductance (or impedance) of the circuit formed by the track rails and shunts.
When a train approaches a crossing, the train's axles and wheels create a short circuit between the pair of rails, which towers the total apparent inductance.
By monitoring the inductance or impedance changes, the location of the train can be determined so that a warning system can be activated.
Unfortunately, grade crossing circuits do not work in all circumstances. For example, grade crossing circuits may not work, or may not work reliably, with poor shunting conditions.
Poor shunting conditions may be caused by low traffic on the rails, which may in turn cause rusts on the rails.
Poor shunting conditions may also be caused by light weight cars on the rails.
Poor shunting conditions may also be caused by vegetation, such as weeds, growing around the tracks, which prevents an electrical connection between the wheels and the tracks.
Based on the foregoing, it is desirable to provide a railroad highway crossing signal electronic assembly with high current sparks to jump gaps between the wheels and the track rails to overcome poor shunting conditions.
It is further desirable to provide an improved railroad highway crossing signal electronic assembly that can manage a C-style circuit.
It is further desirable to make a more cost effective railroad highway crossing signal electronic assembly that uses a single integrated unit to manage train detection and to activate warning lights and gates.
The present invention relates to a method to improve shunt detection on railroad tracks. A high direct current driver provides sparks to a railroad track segment to improve shunting conditions. The invention also relates to an integrated railroad highway crossing signal electronic assembly which improves shunt detection and detects the presence of trains. The assembly includes a housing, a power inverter, a blackout detector, an isolated step down transformer, and a high current driver.
The power inverter may receive voltage from an external power supply, which makes the inverter oscillate to produce an output of power. The power inverter may be connected electronically to the blackout detector. The blackout detector may detect VAC presence and switch to DC power supply when the VAC is absent. The blackout detector may revert back to AC power when it is available. The blackout detector may be connected electronically to the power inverter. The blackout detector may also be connected electronically to the isolated step down transformer.
The isolated step down transformer may take VAC or the output of the power inverter and produce outputs of VAC with multiple ampere capacities each. The isolated step down transformer may be connected electronically to the blackout detector. The isolated step down transformer may be connected electronically to the high current driver. The isolated step down transformer may be connected electronically to AC outlets.
The high current driver may turn the AC output from the isolated step down transformer to a high current output capable of driving multiple amperes of DC current. The high current driver may be connected electronically to the isolated step down transformer. The high current driver may be connected electronically to a high DC current output.
Additionally, the railroad highway crossing signal electronic assembly may be used to manage a C-style circuit.
The devices and methods discussed herein are merely illustrative of specific manners in which to make and use this invention and are not to be interpreted as limiting in scope.
While the devices and methods have been described with a certain degree of particularity, it is to be noted that many modifications may be made in the details of the construction and the arrangement of the devices and components without departing from the spirit and scope of this disclosure. It is understood that the devices and methods are not limited to the embodiments set forth herein for purposes of exemplification.
The present invention relates to a method of improving shunt detection on bi-directional railroad tracks, and to an integrated railroad highway crossing signal electronic assembly. More particularly, but not by way of limitation, the present invention provides a method of improving shunt detection using high current DC output to railroad track rails.
A blackout detector 24 detects presence of the alternating current (VAC) 12 and switches to the DC power supply 20 when the VAC is absent. When the AC power 12 is available, the blackout detector will revert to using the AC power. The blackout detector 24 is connected electrically to both the power supply 12 and to the power inverter 22.
An isolated step down transformer 26 receives 110 VAC or the output of the power inverter 22 and produces four separate outputs of 6.3 VAC nominal with 3 amperes of capacities each. The isolated step down transformer 26 sends an output to a first AC output 28. The isolated step down transformer also sends an output to a second AC output 30. Finally, the isolated step down transformer sends an output to a third AC output 32.
A separate high current driver 34 turns the AC output from the isolated step down transformer 26 into a high current DC output 36 capable of driving up to 3 amperes of direct current (DC).
A first AC output 28 is connected to the rails of the first rail track segment 50. A second AC output 30 is connected to the rails of the second rail track segment 52. A third AC output 32 is connected to the rails of the third rail track segment 54. Alternating current is delivered to each track segment as shown by arrow 120. High current DC output 36 is connected to the first track and third track segments. Diodes 56, 58, 60, and 62 may be connected to high current output 34 to prevent high current DC output 34 shunted in one track to be shorted at the other track.
A C-style circuit may be utilized with the bi-directional railroad tracks 10 having the three isolated rail track segments 50, 52, and 54. Train wheels and axles 18 may shunt the current between one of the track segments. When this occurs, the correspondent rectifier 44, 46, or 48 will be shorted, taking off the direct current in the corresponding segment 50, 52 or 54, de-energizing the corresponding relay 14, 40 or 42. When the direct current is sent to one of the relays, it de-energizes the relay. This de-energizing of the relay causes lights and/or a gate arm assembly 16 to function, which warns drivers or pedestrians that a train is on the tracks and is nearby.
Diodes 56, 58, 60, and 62 prevent the high current DC output 36 from being short circuited. For example, AC output is being delivered to the rails, illustrated by arrows 120, so rectifiers 44 and 48 receive AC voltage and deliver DC voltage, illustrated by arrows 122. When the train wheels enter segment 50 and short out the diode 44, the high current DC output 36 is also shorted out. DC voltage in that segment 50 disappears, dropping relay 14, but keeping the high DC output in segment 54 which is not shorted out.
The separate high current DC output 36 is sent to the track segments 50 and 54 all the time when the AC output has been shunted by the train. This high current DC output provides high current sparks and helps eliminate rust and improves detection of the train. The high current DC output 36 may be attached to the first 50 and third segments 54, but does not need to be attached to the island 52, or the middle segment.
The present invention provides an integrated railroad highway crossing signal electronic assembly which will improve shunt detection on railroad tracks while activating and controlling all warning lights and gate arm mechanisms.
Whereas, the present invention has been described in relation to the drawings attached hereto, it should be understood that other and further modifications, apart from those shown or suggested herein, may be made within the spirit and scope of this invention.
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Brian Solomon, Railroad Signaling, 2003, pp. 145-155, published by MBI Publishing Company, St. Paul, Minnesota, USA. |