Jeff, The cards would stay on the cars once the train hit the main with the exception of shop tags. Those cars would be required by the FRA to be repaired at the point where shopped or if on the road (main) at the nearest location. The chalk marked cross or X would have the inspectors initials, pool mark, date and location one in each of the four quadrants of the cross . This was used for that particular yard's use only, it didn't mean much once the car left that yard. A new pool mark would be added at the next terminal usually next to the previous one and it would start all over again. This pool mark system was in use when I hired on in the mechanical department in 1974 with Penn Central. With Conrail in the early eighties we no longer used this system unless some one missed something big and it caused a major derailment. Then we would break out the chalk and start pool marking again. Eventually we were instructed to use a form (CRB-8 if I recall) and provide the first and last car numbers in our section of each train we inspected. We were wholly responsible for those cars. Glad to help out, and yes I do understand trying to be as prototypical as possible.