I'm guessing this is a sugar ant? I found this an interesting site, as the track in the second photo is made by the ants for the ants, and has been there for years.
Hi Lisa, this is a meat ant, Iridomyrmex purpureus. It Is pretty big, like a sugar ant, but you can see in the third photo the red and purple colours on it. Meat ants are very good at building highways to help them travel quickly between nests or to go out foraging for food. Cheers, Jon