If I understand your question, these are just a part of the model number. Red Caboose and Intermountain will produce a series of cars using the same mold with different road numbers and put an extension on the part number to designate a particular road number kit.
Hope that helps.
I failed to mention that I ask that all responses come to me direct off line so as to not clutter up this list and I will see them much quicker.
