"...you need 3 boxes if you want to make complete circle (if you have no other track). It comes with 8 straight, 4 curved and 8 flexible (which is the equivalent of 2 more curved or 2 more straight). To make a complete circle, you need 16 curved track. Each box comes with 6 curved-type track.
I have the LEGO Harry Potter Hogwarts Express 75955 that didn't come with track and based off another review on this site, I only bought 2 boxes of 60205. I guess hopefully I can get my hands on one more box. Otherwise, the track is nice and the Hogwarts Express fits."