Which of the following is true about the air system in a train?

The statement that the air system may affect brake performance and efficiency is accurate because the air brake system is a critical component of a train's overall operation and safety. The air system functions by using compressed air to apply the brakes on the train cars. If there is any leakage, insufficient pressure, or failure within this system, it can directly hinder the efficiency and responsiveness of the brakes. Consequently, this could lead to increased stopping distances and a higher risk of accidents, emphasizing the importance of maintaining the air system in optimal condition.

Furthermore, while it is important for the air system to function properly, it should not be disregarded during maintenance checks, as the potential for malfunction can have serious repercussions for safety. Ensuring the system operates under proper pressure is necessary for it to function effectively, counter to the idea that it should be maintained under high pressure universally, as excessive pressure could also lead to its own set of issues. Hence, the correct understanding of the air system's role in brake performance reinforces the critical nature of maintaining and monitoring this component consistently.