I'm not a huge fan of hunting right over a trail...but I have done it. What I don't like is the shot angle you end up with a lot of times. Especially if the trail comes and goes so that the deer will never give you a broadside shot.

I've shot a couple straight down, and they didn't go far. They didn't bleed either.

I'm not sure of any other option in your case, so practice your shots at steep angles and give it a whirl.