How To Read Trackside Signs & Markers

APP Marker

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Advanced warning for a signal ahead. Typically can only show a yellow light. Will contain “APP” or “A” below the single light.

Traffic Control (TC)

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Engineer must follow railroad signals (the lights).

TWC (Track Warrant Control)

Equivalent to “end TC”.

Reduce Speed

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Speed through this segment is limited as compared to timetable speed (rest of line).

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Top speed is passenger trains, bottom is for freight trains (at least on CSX controlled tracks). A solid green sign in this shape means “back to normal speed”.

Warning Board

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Limit sign, two miles ahead is either work zone or speed restriction. Operators need to slow down or contact foreman for permission to continue. Can be removed from the ground when no longer needed.

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Temporary reduce speed. Solid red version of this would mean temporary stop. Solid green version would mean end of temporary restriction/work zone.

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