If you consider the arched supports, the cracks occurred about a third of the way up the arch. In one case you could see the squeezed part on the arch, where the separation caused the upper part of the arch to rise while it was being printed. In other cases it seemed to break after the trach that was supported had partially printed.
Here is the good part. It all works, The cracks didn't affect the track. All the tracks work, and the mechanism, also printed in ABS but with 100% infill. The fit of the screw to the turning disk was amazing. it snapped together and held nicely.
I may "fix" the cracks with a 3d pen.
With a 0.2mm layer height, and 25% infill it took about 28 hours to print on my reprap. I will post pics.