An en route failure between an EOT and HEU that results in a loss of emergency application capability from the rear of the train due to loss of front-to-rear communication is called which condition?

An en route failure between an EOT and HEU that results in a loss of emergency application capability from the rear of the train due to loss of front-to-rear communication is called which condition?

• A. NOT ARMD
• B. FR NO COM
• C. VALVFAIL
• D. EOT CALCE

Answer: (B)

When the communication link between the head end unit and the end-of-train device is lost en route, the system can no longer transmit emergency brake signals to the rear. This specific failure is described as front-to-rear no communication. It means the rear of the train cannot perform an emergency application from the back because the front and rear units aren’t talking to each other. This is different from a valve failure (which would affect the brake valve itself) or an arming fault, and there isn’t a standard term like EOT CALCE for this scenario.

When the communication link between the head end unit and the end-of-train device is lost en route, the system can no longer transmit emergency brake signals to the rear. This specific failure is described as front-to-rear no communication. It means the rear of the train cannot perform an emergency application from the back because the front and rear units aren’t talking to each other. This is different from a valve failure (which would affect the brake valve itself) or an arming fault, and there isn’t a standard term like EOT CALCE for this scenario.