Brake Fade and an ABS Light on the Grade Before the Crossing
You are driving a 38,000-pound motorcoach with 42 passengers down a 6 percent grade that is 1.5 miles long. The pavement is wet from drizzle. Your speed has crept from 35 to 48 mph despite steady pressure on the brake pedal. The pedal now feels soft and travels closer to the floor. The ABS warning light is on. At the bottom of the grade, a railroad crossing signal begins flashing red. The speed limit is 55 mph, and traffic is light. You are in fourth gear. There is a gravel escape ramp on the right about 1,000 feet ahead. You smell hot brakes. Your bus has an engine retarder.
1. What is happening, and what should you do immediately?
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The symptoms point to brake fade: the pedal is soft, speed is rising despite steady pressure, and the brakes smell hot. I would not pump the brakes. I would downshift to a lower gear, engage the engine retarder, and apply firm, steady pressure to the brake pedal. If the speed still will not come down, I would use the gravel escape ramp on the right rather than continue toward the crossing. I would keep the bus straight, warn passengers to hold on, and avoid a hard steer at high speed. Continuing down the grade and hoping the brakes recover is the dangerous choice.
2. How does the ABS warning light change your braking technique?
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The ABS light means the antilock system may not function, but it does not mean the brakes are gone. Conventional braking should still work, so I would brake firmly and steadily, not pump the pedal. ABS is designed to prevent wheel lockup, not to shorten stopping distance on every surface. With the light on, I would allow more following distance, reduce speed earlier, and avoid sudden steering inputs. I would report the light after the trip. If the pedal is also soft and fading, the bigger problem is brake fade, so I would use gearing and the escape ramp rather than rely on ABS.
3. What do you do at the railroad crossing if the red lights are flashing?
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If I can stop safely, I must stop before the crossing, at least 15 feet and no more than 50 feet from the nearest rail, and wait until the lights stop flashing and the way is clear. I would not cross while the signal is active, even if I do not see a train. Because I am on a grade with hot brakes, I would first use the escape ramp if I cannot control speed; stopping safely is better than entering the crossing. Once stopped, I would set the parking brake, keep passengers quiet, and proceed only after the signal stops. If the crossing has no gate, I would still stop and listen before moving.