Right Track Toys

Right Track Toys Wooden Train Track 52-Piece Expansion Set, 18 Feet of Track

This is a track-only expansion pack, 52 pieces adding about 18 feet of straight track, curved track, and a curved track switcher, built to work with every major wooden train brand including Thomas Wooden Railway, BRIO, and Melissa & Doug. It's the most-reviewed product in this entire guide, with over 9,600 ratings. Worth buying alongside any of the smaller starter sets above, since every one of them outgrows its included track fast.