Most of the trainers and jockeys now have electronic tags on their motor vehicles as a crack down on money laundring.

You can monitor the vehicles and based on the horses doing their pre-star jumps in the horse float apprxomiately 5-7 minutes you can calculate the arrival time.

The confusing element comes when their the arrivals are either by plane or car.

also when its the home track and put the calculations out a little.