FRED

Flashing Rear-End Device (legacy field term)

Where this acronym appears

End-of-Train (EOT)
EOT is the operational shorthand for the rear of a freight train consist and for the electronic device — formally called an ETD — that monitors brake-pipe pressure at that location.
End-of-Train Device (ETD)
An ETD is the FRA-mandated unit on the trailing car that monitors brake-pipe pressure and transmits status to the locomotive cab.