How Track Circuits detect and protect trains: download your PDF copy!


Track circuits: new white paper in PDF format on, by Jodi Scalise.


Track circuit is the fundamental method of train detection.

The first track circuit, based on a DC technology, has been invented at the and of nineteenth. Over the years, the continuous technological development has enabled to realize track circuits in an increasingly performing way by using AC technology and modulations, but the basic principle for train detection
detection is still the same.

An alternative approach is the Axle Counter system, which uses a “check-in/check-out” logic. By comparing the result for the axles counted in a block section with the result for those
counted out, it is possible to know the status of the track section (free or occupied).

Track circuits contributes also for the vehicle’s speed control, since the electrical signals used for train detection can be exchanged between wayside and on-board for the transmission of speed commands. This can be realized through a modulation of the track signal and is known as “coded track circuits”. Perhaps, no single invention in the history of the development of railway transportation has contributed more towards safety and dispatch in that field than the track circuit……

Click on one of the flags below (English and Spanish) to download the full article in  PDF format. IT’S FAST! IT’S FREE !

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