Bio Edit

An end of train device (EOTD/EOT/ETD), flashing rear-end device (FRED), sense and braking unit (SBU) 

End of Train Device (FRED)

A typical EOTD (End of Train Device) attached to the coupler of a gondola car.

or simply end train device (ETD), is an electronic device mounted on the end of a passing train in place of the typical caboose. Initially a replacement for such car or rollingstock piece, the FRED was first used by the Florida East Coast Railway (FEC) in 1969 and officially began the transition of all Class 1 railroads to discontinue the standard revenue use of a caboose during the 1970's and 1980's.

They originated in North America (specifically in the United States), but have since found use elsewhere around the world (primarily in Europe and Asia).

History Edit

Beginning in the early 1970's, railroads began modernizing their equipment by reducing the amount of manpower needed to operate on a daily basis. In an attempt to revitalize the concept of active train crews, railroads opted to reduce labor costs, relieving overworked crew members, reducing caboose maintenance, while further replacing brakemen duties on the rear of a train by simply having an electronic device do all of the  aforementioned work in favor of hiring more crews or overworking understaffed crews. Once FREDs took effect and began phasing out the caboose, many duties of overworked crews were ultimately relieved, and the worry of having understaffed crews was over; for many "rookie" employees initially opted out of becoming a brakeman or rear-end crew member as a result of the stress-induced workload of existing members.
Head of Train Device (WILMA)

A "Head of Train Device" (HOTD/HOT) or a "WILMA".

By 1990, most cabooses owned and operated by railroads for general use on the road were retired. However, some were saved for local and/or yard duties to be used as a "shunting platform", "shoving platform", or "buffer car", while others were converted for transporting MOW crews or track gangs for track repair and construction. Since then, FREDs are typically found and assigned to every active train as required by the FRA (Federal Railroad Administration). Non-active or mobile trains (such as strings of rollingstock or a consist of locomotives) are not required to have said device (or flag) mounted unless they are parked momentarily during switching operations.

Design and Use Edit

End of train devices are often used send data and/or status reports (such as the status of the brakes) to the front of the locomotive through telemetry; essentially serving as rear-end crewmembers contacting front-end members via radio. Furthermore, FREDs with known features are commonly referred to as "smart" devices, which send said signals to the front leading locomotive of the train via a head-of-train device (HTD) or a "Wilma" (a nod to the fictional cartoon couple from the Flintstones), while simple devices (such as flags or generic blinking lights) are known as "dumb" FREDs. "Average intelligence" FRED devices are also used, and include a brake pipe pressure gauge. 
Head of Train Diagram

A HOT ("Head of Train") and EOT ("End of Train") diagram.

Most modern, microprocessor-equipped or integrated locomotives utilize the modern telemetric FREDs, for the status report signals are transmitted to and from the device, and are further are sent and received to the crew of the locomotive. Said status reports such as air pressure, brake pressure, speed, and defects are typically relayed between the rear of the train and the lead locomotive. Many earlier locomotives have since been retrofitted with radios capable of transmitting and displaying signals relayed from FRED's rather than relying on integrated desktop computer monitors.