On March 12, a train equipped with the ArroWedge had left Joliet, Ill., headed for Los Angeles. As the train was moving through rural Illinois, railroad officials determined the rail car underneath the ArroWedge needed repairs, so the car was pulled out and repaired.Something is missing from the story. The photographs of the crash scene show the Arrowedge, somewhat the worse for wear, dislodged from its car. There had to have been a container underneath the Arrowedge. The container might be traveling empty, but if trains being classified for Butler have to be made up entirely of single-stacked containers, somebody in a yard had a chance to notice.
Sometime between March 12 and March 23, the repaired rail car was exchanged among three railroads within the Chicago area.
"We believe the other railroads improperly classified the rail cars empty instead of being classified as a double-stacked intermodal rail car," [Union Pacific spokesman Wesley] Lujan said.
On March 23, the ArroWedge-equipped rail car was delivered back to Chicago and became part of a larger train headed for Butler, Wis. Lujan said for classification purposes, the rail car was considered to be empty and not a double-stacked intermodal rail car unit.
Properly placed, the Arrowedge serves the same function on a stack train that the nose cone on a truck trailer does, reducing wind resistance on the leading car of the train.