Let me tell you about my problem...
A neighbor has some Lionel and MTH trains for sale due to a move. I told her I would research and give her some recommendations re a price range for each item. I dutifully wrote the number ON EACH CARTON/BOX, and told her I would get back to her with a "current market price" for each item. I am a TCA member, and thought I would look in a few of the more recent TCA catalogs to see what prices these TCA members were asking.
I found all of the MTH items, including those beginning with Cat. Nos. 20- and 30-.
I did not find any of the Lionel items, and the TCA for sale listings used a Lionel ID that was different than the ID on the Lionel boxes. Rather than trying to contact TCA, I just told her I could not offer advice on the Lionel items.....
I guess the question I would ask Lionel (if I cared) is whether this new catalog number system benefits them or us???