Most modern European electric locomotives are now capable of operating on at least two different electrical systems; some can handle four. Many also have multiple pantographs to cope with with countries that have tighter clearances, such as Switzerland (which otherwise has the same electrical system as Austria and Germany).

The big problem has been compatibility of signal systems, as all of the different systems incorporate some type of automatic train stop enforcement. Modern computers have made that much simpler. As long as the engine is equipped with the appropriate pickups for signal indications, the rest is handled in sofware and the indications are displayed in the cab on a computer screen.

The same is true for coping with languages. Tapping a function key changes the language of the in-cab displays from one language to another.

So, in theory, there is now equipment that can now operate from one end of Europe to the other on standard gauge lines.

-- Ernest