I have a ton of Fastrack; a lot of it is O72. I am going to sell it at some point. I can hear every tie when I run an older train on it. Also, since it is hollow underneath, it's like a drum. It's a great option on carpet though. It keeps the carpet fibers out of the train. If anyone needs any, contact me at my email address. I have mostly curves available right now. I haven't done an inventory yet.
George