We opted for an activity table from land of nod instead of a train specific table. Bailey colors on it, plays with legos, his trains etc on the table. And we can buy medium and tall legs for it so one day it will become his desk.
We have one of the activity tables from PBK with the rolling carts underneath, and then I bought a Thomas playboard to go on top and provide a "scene" to play on as well as protect the tabletop....LOVE it, but I was able to get it for $80 at the outlet store, vs. approx $300 retail. The carts are huge and one of them holds ALL of our tons of tracks, trains and most of the "destination" buildings.
We also have the Land of Nod activity table that Wendy mentioned (I guess it's the same one, ours also has the ability to put longer legs on it), and I also love that now for Lego building. We moved it into Jack's room so that the lego's can be contained away from the baby. I will say that the LON table is not big enough for all the different layouts that my boys like to put together with DH. And neither is the PBK table, we actually have a huge wooden fire station on top of the table now, and they play trains on a huge "road rug" that I got at Target. Such a cute and durable rug, and it's the perfect size for their huge layouts. The tables were just too confining....but like I said, we get tons of use out of both tables anyway.