The FRED, or Flashing Red End-of-train Device,
replaces the caboose on today's trains.
FRED's
come in a variety of shapes and sizes. At minimum, it monitors
the brake line for sudden loss of pressure indicating a train
breakapart or a hose failure. The FRED maintains a digital radio
link with the locomotive (457.9375 MHz) and shuts down the power
should a brake failure occur. Any loss of radio contact with the
FRED also shuts down the locomotive. Please also note that
any sudden loss of brake line pressure automatically puts each car in
emergency brake application, so there are redundant safety
systems in place. Some newer FREDs also have the capability
of
applying the brakes from the rear of the train upon the radio link
command from the locomotive. On a mile long train, it
typically takes the last car 6 or more seconds to detect a brake
application from the front of the train which can cause
derailments. By applying brakes from both ends, stopping distance
and safety improves.
(Note: the above
pictures were shot on DM&E right-of-way with permission of the
train crews. Don't be concerned when you see non-flashing FREDs in
daylight hours, they only flash at night; I exercised artistic
license for the above animation)
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