According to most pundits the AutoTrain is the longest passenger train. However, the length varies from trip to trip depending on the passenger/automobile load. Usually seventeen passenger equipment...crew sleeper, sleepers, lounge and diner, coaches with lounge and diner. What varies are the auto racks. Depending on the outbound load or anticipated outbond load out of Lorton, VA. I have had as many as thirty-two carriers and seventeen pax equipment, forty-nine cars total, somewhere around 4,000 feet in length with the engines considered in that length. Hope this helps. Moore Later, AT Engr, retired.