Apparent cause of the breakaway.
"Apparently after a recent examination the buckeye was replaced. The split pin which stops the castellated nut on the shank of the buckeye undoing was not replaced. Over the next couple of days the nut unwound and the buckeye pulled out of its housing. The nut was found on the top of the bogie frame."
Found on another forum that had 9 pages on this one topic.
