摘要 |
A method and apparatus for transmitting an information carrying signal, such as an electromagnetic frequency signal or an acoustic signal, through the tracks of a railroad to a remote position on the track where the information is extracted. The extracted information can be used to relate speed and location of trains, location of obstructions, and/or track conditions. The in situ track (10) is evaluated using an autoranging digital multimeter which establishes the resistance between two opposite rails (12, 14).
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