Today, the ends of trains are monitored by remote radio devices officially called "End of Train" devices, or EOTs, by the Federal Railway Administration. Railroad crews more commonly call these devices FREDs (Flashing Rear End Device). A FRED is attached or hung on the last car's rear coupler. It connects to the train's air brake line. The FRED radios telemetry to the engineer, including brake pressure at the rear of the train, whether or not the last car is moving, and whether or not the flashing red light is working during darkness. A FRED also allows the engineer to set the air brakes from the rear of the train, as much as halving the normal time it would take to set all of the brakes in the train.
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