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).
Read more about this topic: Flashing Rear-end Device
Famous quotes containing the word usage:
“...Often the accurate answer to a usage question begins, “It depends.” And what it depends on most often is where you are, who you are, who your listeners or readers are, and what your purpose in speaking or writing is.”
—Kenneth G. Wilson (b. 1923)