Not that I'm aware of, other than the 2056 was available only one year (1952) it may be a little harder to find and always has a die-cast trailing truck. I think occasionally the 2046 is seen with a sheet metal trailing truck.
I'm sure there are others out there with more experience than I who can weigh in.
I have a 2046 and it runs fairly smooth and smokes up a storm.
Mike