Thanks west lakes,
At least the civil aircraft industry ended up standardising largely on 115V 400Hz and 28VDC, unlike the railways, where everybody went their own way.
1.5kV DC, 3kV DC, 750V DC third rail, 25kV 50Hz, 15kV 16 2/3 Hz.... take your pick. And there are certainly others.
Hence some TGVs runing on international routes, and the Thalys, and the Eurostar, which are all "tri-tension" (but not the same voltages, LOL)..