What should be checked if the brake pipe is not charged during troubleshooting?

When troubleshooting a situation where the brake pipe is not charged, checking the circuit breakers is essential because they are critical components in the electrical system that control the air brake system. If a circuit breaker is tripped or malfunctioning, it could prevent the brake pipe from receiving the necessary air pressure. This could lead to a failure in the brake system, affecting the overall functionality and safety of the train.

By verifying the circuit breakers, you can ascertain whether there is an electrical issue preventing the brake system from operating correctly. If any breakers are tripped, resetting them or addressing the underlying causes can restore proper function. This step is a fundamental part of diagnosing issues with the air brake system.