The RhB is full of interest and runs through some fantastic scenery, but one of my favourite bits is the street running from Chur at the start of the Arosabahn.
A pair of Ge4/4iis trundle along the main road with a long train in readiness for the returning day-trippers from the popular resort of Arosa. The double track is relatively recent, presumably put in to keep the trains on the same side of the road as the cars.
