Off-Air Train After a 10-Hour Yard Stand
A 86-car mixed freight, 5,900 feet, 3,900 tons, single C44, has been sitting on a yard track for 10 hours with the brake pipe at 0 psi. Temperature is 18°F and falling. The yardmaster wants it out before the next snow band. When you arrive, the car inspector says the train was 'tested yesterday' and only needs air. You notice the rear car's brake pipe pressure gauge is at zero and the hand brake is applied on car 12. The train has not been inspected since arrival except for a visual walk-by. Your railroad requires a brake test after a train has been off air this long. The train is scheduled to pick up 12 cars at the next terminal 40 miles away. You have 45 minutes before the crew expires.
1. What brake test is required, and why is 'it was tested yesterday' insufficient?
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Because the train has been off air for 10 hours, the prior day's test is not valid for departure. Air brake systems can leak, hand brakes can remain applied, and cold weather can freeze or stiffen components; a visual walk-by does not prove that brakes apply and release. Your railroad's rule requires a brake test after the train has been off air this long. Treat this as an initial terminal test, or the applicable terminal test your rule book specifies for an off-air train: release all hand brakes, charge the brake pipe to the required pressure, allow full charge, measure brake pipe leakage, and inspect each car for brake application and release, piston travel, and rigging condition. Do not accept 'it was tested yesterday' as a substitute, and do not depart on a 10-minute charge just because the yard is behind.
2. Outline the sequence you would use, including charge time and what you check at the rear.
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First confirm all hand brakes are released, including car 12. Charge the brake pipe to 90 psi and allow enough time for the entire train to charge; on an 86-car train in cold weather, that means watching the rear pressure, not just the head-end gauge. Perform the leakage test with a calibrated gauge and compare rear pressure to the head-end requirement. Then make a brake application and walk the train to confirm each car's brakes apply and release; check piston travel and slack adjusters. Pay particular attention to cars that were hand-braked or exposed to snow and ice. If the rear does not reach the required pressure, inspect for closed angle cocks, ice, or a leak before proceeding.
3. The rear remains at 78 psi after 20 minutes of charging while the head end is at 90 psi. What do you do?
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Stop and investigate. A 12 psi gradient after 20 minutes indicates a restriction or leak: a partially closed angle cock, an ice blockage, a broken pipe, or a defective DPU. The train is not fully charged and cannot be given a valid brake test. Close the head-end angle cock, inspect the train line, check the rear gauge against a second gauge, and look for a closed branch pipe cock or a kink. In freezing weather, ice in a dirt collector or hose is a strong possibility. Do not depart until the rear pressure is within the allowable gradient and leakage is within limits.