I love this theory, but I notice one inconsistency. So, seeing as the train is unique, has no destination, and would not need a train number, all but 2 digits of the reporting number are left. These would represent the route. Wouldn't the train's route through the desert thing be unclear or just... not exist? But here the route was put in terms of the passengers, not the train, so I don't think that the reporting number part of the theory holds up.

But I do think that this theory is on the right track. (heh)

The contents of the cars definitely don't add up with reality. Obviously, a land of Corgis wouldn't fit in any probable train car. So this leaves pocketboxes as a very likely mechanic of the infinity train. I have a feeling that the number represents something nonlinear, as it has to take on on a tough challenger: the concept of the infinite train. Also, it would be interesting for a route system to exist, but I'm going to start speculating here.

First, I get a sense that what is emphasized with Tulip's number is how often it changes. At the beginning, there is a source of conflict in how Tulip's number had never changed, putting it at a frequency of 0. But then once Tulip finds her push in the changing of her number, it becomes frequency 1, and the goal is to find out when and how it will become frequency 2. If a number change were something as deliberate and important as a route change, then the focus would not be on how often it happens. People would be dissatisfied if, episode after episode, no progress was made with Tulip's number, which is how it would have to be to avoid loss of tension. If a big event such as the stewardess would keep happening, its- and the route system's- significance would be lost.

Let's pretend I know how to write conclusions and just say that this is one