I think the question is whether the tank would have been transported on US rails in winter of 1943 since that is the approximate time and railroad location Eric gave in his original post. He stated he was pretty particular in how he chose the time and equipment. So given that I think Eric stated that his train is already too long at this point, it could save him some time by not having to build the tank if it truly does not fit into the scheme, or he could just choose to ignore the information and build the tank anyway just for kicks.
My take from the information provided is that the winter of 1943 is Jan/Feb/March and that the tank likely would not have been on the rails at that time.
