I was on a westbound Zephyr a few years ago which was already 6 hours late due to being caught behind two different freights with frozen air in Colorado, one east of Denver, and one up near Winter Park, when the train went into emergency in Nevada. Turned out that an air hose had come loose on the diner. After reconnecting, pumping up the air and testing the brakes, the train restarted. There was a terrible vibration that I could feel in the sleeper. After another inspection, it was reported that there was a 2 inch pipe wrapped around the axle on the diner, and that was what had knocked the air line loose. Amtrak had to dispatch a welder to come cut the pipe off. Fortunately, we had stopped opposite a siding, so freights were able to get around us while we waited. And while we waited, the conductor did another inspection of the train, and found the origin of the "pipe." It was a part that had fallen off one of the coach trucks. After what were apparently fairly long discussions with Amtrak maintenance, we were allowed to double up the coach passengers into once car and proceed at 10 MPH to a nearby town where there was a siding. The car with the damaged truck was dropped on the siding. After the train restarted, the engineer called the conductor and asked how her "customers" were. She told him that the passengers gave her a round of applause when she got back on after dropping the coach! We were 12 hours late to Emeryville.