.. DC voltage was common in some cities, notably New York,
I think at around 110 volts. DC was convenient for operating
traction motors of the sort used in elevators so it was
continued until a surprizingly late date. DC was also
available in some other US cities but its beyond my recall
which ones. 110 VDC was also common on shipboard.

Richard Knoppow
Los Angeles
WB6KBL

110VDC on ships, Oh yes! Partner and I repairing radar
on one such ship, bravely plugged in our trusty Weller
soldering gun and pulled the trigger. Nothing for a few
seconds, and then a little curl of smoke. When trigger
was released, it hissed, breathing fire and sparks out of ALL
the air cooling vent slots. Throwing it on the deck and
stomping on it only aggravated the fireworks. Stone
faced Skipper calmly pulled plug from wall, and I think
he lost some admiration of our technical competence.
Old Chief Lynn, W7LTQ