This may be another reason to use roundabouts instead of stop lights or stop signs at intersections.
Don't trains usually have to accommodate the potential for standing passengers and thus have to have a much smoother acceleration curve than is strictly necessary for car comfort?
I would expect that trains have to accommodate the fact that they're trains as well. I would expect trying to stop/start a train traveling at 60mph without damaging the tracks on which it runs would require rather more time than a car.