Just fine.

The overhead line is the equivalent to a third rail, while the rails provide the earth connection.

So it can just be a continuous diamond shape above, same as the rails below.

Child's play compared to the old "tram squares" in Melbourne where a 600VDC tram crosses a 1500VDC train line:

(Photo courtesy of WongM)

they usually use metal plates under and touching the wires to make a seamless transition

These are fairly common on railroads so they can't be too bad on maintenance