Transporting Passengers and Air Brakes
This domain pairs passenger-carrying rules with the air brake system and the pressure checks that prove it works.
Passenger rules
- No standees forward of the standee line, and doors closed before the bus moves.
- No hazardous materials aboard beyond the small allowed quantities.
- A bus carrying passengers must stop at railroad crossings, stopping between 15 and 50 feet from the nearest rail.
- Check for sleeping or left-behind passengers after each run, and never fuel with passengers aboard.
Air brake system
- Three systems: service brakes through the foot valve, parking brakes through spring brakes, and the emergency system that applies the springs automatically.
- With the engine running, pressure should build from 85 to 100 psi within 45 seconds.
- The low-pressure warning must activate before pressure falls to 60 psi, and the spring brakes apply between 20 and 45 psi.
- Drain the air tanks daily to remove moisture, and watch for frozen lines in cold weather.
Worked example
With the engine running and pressure at 85 psi, you time the build to 100 psi at 30 seconds. That is inside the 45-second limit, so the compressor passes. If it took 60 seconds, the compressor is weak and you write it up, because a compressor that cannot keep up will not survive a long downgrade or repeated brake use.
Traps that cost marks
- Confusing the 60 psi warning with the 20 to 45 psi spring brake application.
- Skipping the daily tank drain.
- Stopping a passenger bus too close to, or too far from, a crossing.
- Loading passengers before checking that doors close and seal.