US 7,254,467 B2Granted

Digital train system for automatically detecting trains approaching a crossing

AssigneeGeneral Electric Company

InventorsJeff Fries, Roger Fitz, Robert M. Morris

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Abstract

A system for automatically detecting the presence of a train located within a detection or surveillance area of a railroad track associated with a railroad grade crossing. The system includes a transmitter unit that transmits a detection signal. The system also includes a receiver that receives a detection signal. A receiver unit receives one or more signals. A processor coupled to the receiver unit is configured to process the received signals and determine the presence, absence or movement of a train or signal within the detection or surveillance area. The processor unit is configured to initiate an action when the processor determines the presence or the absence of the train or one or more detection signals. The current invention also includes a method for automatically detecting the presence of the train located within a surveillance area associated with a railroad grade crossing area.

Claims25

Dependent claims

A train detection system for detecting the presence and/or position of a railway vehicle within a detection area of a railroad track, the railroad track having a pair of rails and an identified impedance within the detection area, and wherein the presence and/or position of the railway vehicle within the detection area changes the impedance of the track, said train detection system comprising:

a first transmitter connected to the rails of the railroad track for transmitting along the rails a first signal having a predetermined magnitude and a predetermined operating frequency;
a receiver connected to the rails for receiving the first signal;
a first data acquisition unit coupled to the first transmitter and the receiver and responsive to the transmitted first signal and the received first signal to generate first multiplexed analog signal representing the transmitted first signal and the received first signal, wherein the first data acquisition unit includes:
a first feedback circuit for detecting a first transmitted voltage signal applied to the rails via the first transmitter, a first current signal transmitted along the rails via the first transmitter, and a first received voltage signal received by the receiver;
a first filter coupled to the first feedback circuit for filtering the detected first transmitted voltage signal, the detected first transmitted current signal, and the detected first received voltage signal;
and
a first multiplexer coupled to the first filter for multiplexing the filtered first transmitted voltage signal, the filtered first current signal, and the filtered first received voltage signal to generate the first multiplexed analog signals, and wherein the processor calculates the impedance in the approach detection area as a function of the difference between first transmitted voltage signal and the first received voltage signal, and the first transmitted current signal;
a first converter for converting the first multiplexed analog signal into a plurality of first digital signals corresponding to the transmitted first signal and the received first signal;
and
a processor responsive to the first digital signals for processing the first digital signals to determine the frequency and magnitude of the transmitted first signal and the received first signal.

7 more elements

A method for detecting the presence and/or position of a railway vehicle within a detection area of a railroad track, the railroad track having a pair of rails and an identified impedance within the detection area, and wherein the presence and/or position of the railway vehicle within the detection area changes the impedance of the track, comprising:

transmitting along the rails a first signal having a predetermined magnitude and a predetermined operating frequency;
transmitting along the rails a second signal having a predetermined magnitude and a different predetermined operating frequency;
receiving the first signal being transmitted along the rails;
receiving the second signal being transmitted along the rails;
generating a first analog signal representative of the transmitted first signal and the received first signal;
generating a second analog signal representing the transmitted second signal and the received second signal;
converting the first analog signal into a plurality of first digital signals corresponding to the transmitted first signal and the received first signal;
converting the second analog signal into a plurality of second digital signals corresponding to the transmitted second signal and the received second signal;
and
processing the first digital signals to determine the frequency and magnitude of the transmitted first signal and the received first signal to determine an impedance of the track as an indication of the presence and/or position of a train within an approach detection area, and processing the second digital signals to determine if a magnitude of the received second signal is below a threshold value as an indication of the presence of a train within an island detection area.

7 more elements

A train detection system for detecting the presence and position of a railway vehicle within a detection area of a railroad track, the railroad track having a pair of rails and an identified impedance within the detection area, and wherein the presence and/or position of the railway vehicle within the detection area changes the impedance of the track, said train detection system comprising:

a first transmitter connected to the rails of the railroad track for transmitting along the rails a first signal having a predetermined magnitude and a predetermined operating frequency;
a second transmitter connected to the rails of the railroad track for transmitting along the rails a second signal having a predetermined magnitude and a different predetermined operating frequency;
a receiver connected to the rails for receiving the first and second signals;
a first data acquisition unit coupled to the first transmitter and the receiver and responsive to the transmitted first signal and the received first signal to generate first multiplexed analog signals representing the transmitted first signal and the received first signal;
a second data acquisition unit coupled to the second transmitter and responsive to the transmitted second signal and the received second signal to generate second multiplexed analog signals representing the transmitted second signal and the received second signal;
a first converter for converting the first multiplexed analog signals into a plurality of first digital signals corresponding to the transmitted first signal and the received first signal;
a second converter for converting the second multiplexed analog signals into a plurality of second digital signals corresponding to the transmitted second signal and the received second signal;
a first digital signaling processor responsive to the first digital signals for processing the first digital signals to determine if the frequency of the received first signal is within a first passband frequency range, wherein said first passband frequency range is a function of the frequency of the transmitted first signal;
a second digital signaling processor responsive to the second digital signals for processing the second digital signals to determine if the frequency of the received second signal is within a second passband frequency range adjacent to the first passband frequency range, wherein said second passband frequency range is a function of the frequency of the transmitted second signal;
and
an external processing system responsive to the first digital signals for processing the first digital signals to determine the frequency and magnitude of the transmitted first signal and the received first signal to determine an impedance of the track as an indication of the presence and/or position of a train within an approach detection area when the received first signal is within the first passband frequency range, and wherein said the external processing system is responsive to the second digital signals for processing the second digital signals to determine if the magnitude of second signal is below a threshold value as an indication of the presence of a train within an island detection area when the received second signal is within the second passband frequency range.

8 more elements

Dependencies are inferred from the claim text.