I am trying to come up with a HCD layout that has a crossover. The actual crossover I want to do is an over/under not on the same plain. So what I am thinking is a 2% grade for both tracks. I want one to drop down and the other to rise up splitting the clearance evenly. Is a foot enough of a flat before rising or dropping again? Obviously I would still have cars rising as the loco starts dropping and vice versa. I am looking to break up the monotony and have an excuse for a trestle. Thanks for all the help.