I have read in an old railway book that after the second world war trials were done in Northern Italy with 3Ø power at 3000 Volts AC.
There were 2 overhead catenary wires, and the rails were the 3rd phase and were grounded. This system was used for quite a few years after it was abandoned and 3000 Volts DC was adopted to harmonise with the rest of Italy which uses 3000 V dc.
It must have been an absolute nightmare at points to avoid shorting out the overhead supply. 2 pantographs were used for power collection.
Also a limited section of speeds were available by changing pole pairs over.
I see if I can find the book or get some more info on gooogle.
