Electric buses. I'm not talking about the current crop of battery powered vehicles but buses that ran on a pair of overhead electrical wires. Riding one was an adventure. At the main intersections, there were junctions and insulators in the overhead wires to allow cross-traffic electric buses to pass through the intersection and maintain power, and the conductor rods on the busses would spark like crazy and the interior lights would flicker as it hit those junctions. And every now and then one of the metal conductor rods on the roof would jump off the wire, bringing the bus to a complete stop. The driver would have to get out and use a long stick to gingerly maneuver the rod back onto the overhead wire, usually with lots of sparks, and then the lights would come back on and the journey would resume. Those conductor rods mounted on the roof had a pivoting mount which allowed the rods to follow the overhead wires (usually) even when the bus was turning into and out of the curb lane. It was interesting to see those things in action.
As a little tyke standing on the sidewalk watching these buses with all of the angry sparks flying, it looked fascinating and almost cataclysmic at times. I was in awe of the bravery of those drivers when they had to fix the overhead conductors! And I always wondered what voltage they operated on.
Edit: Apparently Seattle still uses some
electric buses. The ones in my old neighborhood looked like
this.