Which description correctly defines an inverse gradient?

Which description correctly defines an inverse gradient?

• A. The permanent gradient caused by a mechanical fault
• B. The gradient that exists when the system is fully charged
• C. A false gradient
• D. The temporary condition when brake pipe pressure is higher at the rear of the train than at the head end during a service brake application

Answer: (D)

Inverse gradient is about how brake pipe pressure is distributed along the train during a service brake application. It describes a temporary situation where the brake pipe pressure at the rear of the train is higher than at the head end, which is the opposite of the usual pattern. This happens because air along the train line doesn’t equalize instantly when braking begins—factors like train length, line volume, and valve timing can create a momentary reversal before pressures settle. It’s a transient condition, not a permanent fault, and it differs from a gradient caused by a mechanical fault, a gradient only seen when the system is fully charged, or a false gradient.

Inverse gradient is about how brake pipe pressure is distributed along the train during a service brake application. It describes a temporary situation where the brake pipe pressure at the rear of the train is higher than at the head end, which is the opposite of the usual pattern. This happens because air along the train line doesn’t equalize instantly when braking begins—factors like train length, line volume, and valve timing can create a momentary reversal before pressures settle. It’s a transient condition, not a permanent fault, and it differs from a gradient caused by a mechanical fault, a gradient only seen when the system is fully charged, or a false gradient.