Nice catch. I rewatched the replay and he took a little jump and switched leads over the tracks from where the starting gate was moved. If you watch closely you can see it is where they raked up the tracks but he must have just been spooked enough to try to avoid them. Not sure he wins without switching leads, but it certainly impacted him in deep stretch.
https://www.youtube.com/watch?v=_QUWc4L3N8o
https://www.youtube.com/watch?v=_QUWc4L3N8o
