Radio-based control of railroad train brakes is effected in which brake
systems are computer controlled. An End of Train (EOT) system is used in
which microprocessor circuits of a Locomotive Control Unit (LCU) and an
EOT unit are programmed to perform these and other functions. The computer
system has several states. On power on, the system enters the Setup state
during which the system stores about one minutes worth of both brake pipe
and equalizing reservoir pressure data. This data is later used to
determine the rate of change of these pressures to determine stability.
Once setup is complete, the system enters the Stability state during which
operating pressures are determined. When the equalizing reservoir
pressure, the brake pipe pressure and the brake pipe pressure at the end
of the train are stable, the EOT unit is commanded to update operating
pressures stored in its microprocessor control circuit. Once the several
pressures have been found to be stable, the system goes to the Release
state. The system makes transitions between the Release state and the
Stability state until a predetermined decrease in brake pipe pressure is
detected. At this point, the system makes a transition to the Application
state. In this state, determinations are made as to whether to transmit
brake commands to the EOT unit from the LCU or to return to one of the
Stability or Release states. In any of these states, the system can
immediately enter the Emergency state to the Setup state, if setup has not
been completed, or to the Release state if setup has been completed.