Years ago I had a train guy, who didn't understand it very well, try
to tell me about how an electric locomotive worked. He was a bit vague
about 'lectricity but did talk a lot about some sort of coils or
resistance grid on the top of the engine that got very hot under
certain conditions.

My first job straight out of college was at the National Carbon Company in
Cleveland.

As I was being given a plant introduction tour saw a couple of guys at
bandsaws cutting carbon blocks into small pieces.

Was told these guys worked on piece rate and were the highest paid hourly
employees in the place.

All those little carbon pieces ended up becoming carbon brushes for
Electromotive train engine DC motors.

Lew