Car was in a westbound train (empty). The engineer thought he could let the train drift through the sag a Lobato by letting the train roll off the grade on the uphill side of the bridge. There were about 6 empty tanks in the middle of 50 cars of pipe. The slack came in and popped this car right out of the train.
Info came from the guy firing that day.
BTW, the grass still doesn't grow when this car leaked goo on the ground....