I got to 500 by gen 12, and then it seemed to run out of track.An hour and a half later, with 75% of the models making it to 500, the track never got any bigger.
Hmmm, looks like in v2.0, you get to 384.(something), and then it's the times that your machines cover it that matters... I got a 27 second monster (took 27seconds to cover the 384.2 distance ).