Where is the system maximum EDBA measured for intermodal or manifest trains?

Where is the system maximum EDBA measured for intermodal or manifest trains?

• A. At the head end
• B. At the tail end
• C. At the locomotive air brake reservoir
• D. At the caboose

Answer: (A)

The main idea is that the emergency brake demand travels from the front of the train toward the rear. When an emergency brake is activated, the signaling and the big change in brake pipe pressure initiate at the head end where the locomotive or leading control is located. That is where the braking action begins and where the magnitude of the signal is the strongest. As the emergency signal moves down the train, it gets attenuated by line resistance, valve leakage, and the time it takes for each car’s brakes to respond, so the later cars experience a smaller instantaneous demand. Because of this propagation, the system’s peak EDBA is observed at the head end. The locomotive’s air brake reservoir is part of supplying brakes but does not reflect the train-wide peak braking demand, and the caboose or tail end will not show the maximum due to the distance from the initiating source. This holds true for intermodal or manifest trains as well, since the braking signal originates at the front and weakens as it travels back along the train.

The main idea is that the emergency brake demand travels from the front of the train toward the rear. When an emergency brake is activated, the signaling and the big change in brake pipe pressure initiate at the head end where the locomotive or leading control is located. That is where the braking action begins and where the magnitude of the signal is the strongest. As the emergency signal moves down the train, it gets attenuated by line resistance, valve leakage, and the time it takes for each car’s brakes to respond, so the later cars experience a smaller instantaneous demand. Because of this propagation, the system’s peak EDBA is observed at the head end. The locomotive’s air brake reservoir is part of supplying brakes but does not reflect the train-wide peak braking demand, and the caboose or tail end will not show the maximum due to the distance from the initiating source. This holds true for intermodal or manifest trains as well, since the braking signal originates at the front and weakens as it travels back along the train.