…and, the insanity continues…
http://bangordailynews.com/2015/02/23/news/portland/train-collides-with-car-in-yarmouth/
They are not as heavy as freight trains, but are often moving faster, and they still have a limited number of wheels to brake. No train moving at 40 mph can stop to avoid vehicles in their way, or they would be. Train crews are at risk every time they collide with something and engineers do try to brake to avoid collisions when they see the possibility developing. The problem with braking trains isn’t that the brake systems are inadequate, it is that steel wheels on steel rails don’t provide much friction. It’s not at all rare for brakes to lock up and what results is a wheel with a flat spot. A passenger train doing 40 might be able to stop in half the distance of a freight train, but that can still be quite a long ways. Unless you want the gates to come down several minutes before the train gets there. I don’t think that would be popular.
As to friction: I seem to recall it being said–back when sports teams traveled by rail–local miscreants would put lard on the rails, so that the train would overshoot the stop by 1/4 mile or so. “Welcome to the Neighborhood!”