I started to think more about the car attributes and which ones are really necessary. I had said that we need the Car Type and Nominal Length, but not always the other four attributes. Now I am thinking that they are all optional. Stay with me for a moment, and it may make sense. Ok, we do need the Car ID, namely the Road and Number, otherwise we can’t find the car to move, and we need the actual length to make sure there is space for it. But as for the other things, they are only used to select suitable shipments for the cars when they get restaged. It would work even if we had all six attributes blank, meaning “don’t care”, or “unknown” for everything. That means that such a car could be given any role, as there is nothing to match on. While this sounds silly, it is a good way to get a new system started by generating lots of car movements without any real regard to what is going where and in what type of car. Not very prototypical for sure, but it can help prove out a train scheduling scheme and get lots of cars moving about. There is nothing really that dictates that only one specific type or class of car can be delivered to a certain industry. It is all 4’- 8 1/2” between the rails and any car can physically go anywhere. After some experience is gained with how the cars move with the trains according to their timetables, more specific roles and car types can be introduced to narrow things down and get more prototypical movements.