What minimum accumulator pressure (psi) will provide ten emergency brake applications?

• A. 3500 psi
• B. 3200 psi
• C. 3600 psi
• D. 3800 psi

Answer: (A)

Accumulator air is the stored power that powers emergency brake applications. When you initiate an emergency brake, a fixed amount of air is drawn from the accumulator to apply the brakes on the train. Because you need enough air for ten such applications, you must start with enough pressure to cover that total demand while keeping the accumulator above its minimum safe level. In this scenario, 3500 psi is the threshold that guarantees ten emergency brake applications can be made. Pressures below that, like 3200 psi, wouldn’t provide enough air for ten uses; higher pressures, such as 3600 or 3800 psi, would also work but aren’t the minimum required.