What is the minimum percentage of cars with operative air brakes in a train that is enroute?

What is the minimum percentage of cars with operative air brakes in a train that is enroute?

• A. 85%
• B. 75%
• C. 90%
• D. 80%

Answer: (A)

In motion, a train relies on most of its cars having working air brakes so the brake system can respond uniformly and stop safely. The standard requires eighty-five percent of the cars to have operative air brakes. That level provides enough braking mass across the train so the brake pipe pressure can be applied consistently and the train can decelerate predictably. If fewer cars had functioning brakes, braking would be uneven and stopping distance could increase, creating safety risks for the train and following traffic. The other percentages don’t align with this safety threshold: ones lower than eighty-five percent would permit too many inoperative cars, and one higher percentage is more restrictive than necessary for typical operation.

In motion, a train relies on most of its cars having working air brakes so the brake system can respond uniformly and stop safely. The standard requires eighty-five percent of the cars to have operative air brakes. That level provides enough braking mass across the train so the brake pipe pressure can be applied consistently and the train can decelerate predictably.

If fewer cars had functioning brakes, braking would be uneven and stopping distance could increase, creating safety risks for the train and following traffic. The other percentages don’t align with this safety threshold: ones lower than eighty-five percent would permit too many inoperative cars, and one higher percentage is more restrictive than necessary for typical operation.