It seems to me a better idea would be to use some math, as far as distances and speeds, and set up a vehicle only high speed rail line.
Imagine the two story car carrier trucks used by car dealerships, but as trains with thin, streamlining walls and roof. Cars drive into position and are secured. It takes the train several miles to accelerate to maybe 180mph, and even more miles to brake when approaching the end. So the route would be worth it if it was 200-300 miles. And the further they went without halting, the better the deal.
Hope one in the middle doesn’t have a wheel bearing go out or some such