Michael--
I put up a post a couple of weeks ago regarding a conversation I had with NYRA track superintendent Jerry Porceli. The gist was that what has changed over the years is track composition (more sand, less clay, and not just at Nyra tracks), and that has made tracks slower than they were when dry, and faster than they were when wet.
As a side note, I was talking about this with Elliot Walden, and he said that CD started going back the other way (adding clay) the year Monarchos won. The recent fast Derby times are a function of both faster horses and a faster track.
