In the old days when N-scale was new (1970), I would run 85' passenger cars from Atlas and MRC (as below) on dual track of 9.75" and 11.00" radius respectively. It was really close but they passed without scraping each other. Both brands had both truck mounted couplers. I would guess same would apply to passenger cars these days.Looking for n scale Amtrak passenger cars for tight 9.75 radius curves