Railfan Usage
Railfans and railway photographers sometimes monitor the FRED frequencies as an early warning system to detect approaching trains. FREDs in North America operate on the 452.9375/457.9375 MHz frequency pair with the exception of those operated by Norfolk Southern Railway, which uses AAR channel 67 (161.115 MHz). Railfans often program these frequencies into their radio scanners, which can provide a handy indicator of train activity (usually 2–5 miles, transmitting at 2 watts).
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