Originally posted by JBEX
Fluctuating temps that can bring rain also confuse the situation. You can not grade mud, so once it's wet, there is not much you can do but harrow it, float it( smooth it out to let the water come to the top and evaporate or run off), or roll it ( a row of wheels that packs the dirt). So you can see how sometimes with approaching wet weather, the track might need to be over graded, or graded when it might not really need it, because it won't be gradable for a few days after it gets wet.
These actions by the track superintendent can and do create favorable positions on the surface. He tries his best to keep it even, but sometimes it's just impossible.
Harrowing is the grooming of the track you see between races.
Grading the track is 1 or 2 road graders peeling off cushion and moving it back up the pitch of the track towards the crown , which is the highest point of the track about 3/4s of the way out from the inner rail towards the outer rail.
It really is harder than you might think.
Hope that helps explain it better.