Apparently the track being pulled out has happened to a couple of us. My experience relates to a deck mounted track.

The bolts, with the washers, literally pull through the fiberglass, bending up the track, which puts strain on the next bolt in the line, and then that too gives way. However, it was the stern end of the track that pulled out. I don't know if that would have been as likely if the car had been more centered in the track.

That is why, in my opinion, you should use a metal bar under the track that links the bolts so that the stress area on the fiberglass is more than simply the diameter of a washer.