> > Do you know that, up to the 20s, all streetcar services in Italy ran on the left hand side [...]

> Big problems! Crossing at junctions must have been fun.

Also in the narrow roads in the city centres...
Usually motorcars used the rightmost part of the road, while streetcar tracks were in the centermost part; the big problem in the 20s, in fact, was the huge number of people hit by other vehicles while getting on or off by a streetcar.

> Trains here run on the left, at least when there's only two tracks. Big commuter lines have anything up to eight tracks and then it's anybody's guess.

Railway tracks - except those leading to terminal stations and on single track lines - are always used as one-way (a train is always running either in the "legal" or "illegal" direction: if the signals the engineer sees on his right-hand side have a round shape, it's the legal direction; if the shape is square, it's the illegal one); a train may be diverted on the illegal track -with a speed limit of 60km/h or 20mph on British lines- only in case of emergency (or if it's approaching a station, the "legal" direction is already busy and no traffic is incoming on the opposite direction).
This set of rules *should* avoid collisions also when the signalling system goes out of order.

AP.