K.M.
K.,
Check out the NILO table. http://nilotoys.com/ It is solid wood. Your whole family can stand on it without a problem!You can buy bins for under it and once your son outgrows using it as a train table you can add extenders to the legs to make it a higher work table. I have two of them. My boys started playing trains on them at 2 1/2 and still play wooden trains (Thomas) on one (my boys are now 4 & 6). The other table they use as a knex station to build all kinds of crazy things. These tables are pricey but so solid- much nicer than the Thomas tables, the ones at Costco, or really any other train table I've ever seen. If you buy the NILO table be sure to get the train table, not the lego table. The lego table is smaller. The train table fits a Thomas play mat if you wanted to buy one to put on it. I didn't, we used the one that came with the Nilo table.
For the most part the wooden train sets all fit together and are interchangeable. Brio make high quality train sets that work well with the Thomas stuff. My boys liked having the actual Thomas trains because they recognized them from the videos but I bought lower cost, less well know sets to get extra track and it all fit together.