I'm sure there are others that can top this but for me it was my very first Amtrak trip in July 2000 on the Sunset Limited. Supposed to leave LA Union at 10:30 in the evening ended up being closer to 2 am (overheard on scanner about something needed to be welded back on the locomotive). Dozed off after a bit but woke up not going anywhere, finding out later that we were in Colton for nearly 2 hours, unknown as to why. By the time we got to Gila Bend, the crew ran out of time (crew change normally in Tucson) and so had to wait there for replacements. In the mean time, goodies were ordered to stock up the train like ice, etc. Within an hour after leaving there, we stopped again in the middle of nowhere in 110 degree heat, this time due to a passenger collapsing from a diabetic coma. Had to wait for a helocopter come and take that person away. Stop and go after Deming in a middle of a thunderstorm--nice light show though. By the time we got into El Paso, my destination, it was well after midnight when we should have been there around 3:30 pm. My third trip on this same route (Aug 2004) was just as bad only it was after 1 AM in El Paso.