European railways use a vast variety of systems. As far as I know Italy and France are mostly 1500V DC, I think there are 3000V systems, Austria, germany and some other countries have agreed on 15000V 16 2/3 (or more correctly now 16.7) Hz. Tram and subway systems are even worse, they run on 500V, 550V, 650V, 750V, 900V, 950V,... Vienna alone has 650V (not sure, maybe the Trams are 750, not 650), 750V catenary, 750V third rail, 950V (all DC) and 15kV 16 2/3 Hz AC. The Vienna Stadtbahn network that was opened as an urban steam railway system with interconnected lines and trains going as far as 100 or more km out of town is now split up into 3 isolated systems. 1 of the 3 lines uses 750V DC third rail (Vienna subway system), 1 is 750V catenary (tram style, but officially called subway), only the third line is still full railway system, 15kV AC, but the connections to the surrounding area have been chopped as well, even though they could reopen them any day.
