Many moons ago I worked for a company selling to the electric power industry. One of our customers was American Electric Power. At the time they had the highest voltage transmission line in the USA. It was a 765,000 Volt line. YES, 3/4 of a million Volts! The line ran from Indiana/Ohio to Virginia. They had a trolley car that ran on the lines. The line crew sat in the trolley and repaired the wire cable bundle while the system was engaged. The guy I was working with said most of the work they did was repair of the cable (wire) from bullet nicks.
I couldn't believe people would actually do this for for a living. It must have been possible to hold your arm out and get a corona off the tip of your finger. Jeeze, it gives me the shakes just thinking about it. I was so amazed by the whole idea of this, I forgot to ask how they got into the trolley while the line was engaged.