Given these are the kind of obstacles a Google driverless car has to navigate around, machines may be at the point they can match humans here. Of course this is a much more fancy, expensive level of automation than the "docklands light railway" type.
If a driverless car goes wrong, it's very unlikely to kill more than a double-handful of people.
A 5000-ton freight train capable of barreling along at 100km/h while carrying 50 tanks of propane or anhydrous ammonia or similar is an entirely different risk case ...
