Steve, prior to the depression, even here in the US voltage and frequency differed by area.
I know most of Southern California had 50Hz until the late '30s, and some parts until after WWII. No doubt there were many isolated mining camps with 25Hz. And of course DC mains were still common in urban centers as late as the '50s.
What other areas of the US, after 1920, would have had frequencies other than 60Hz?
In Chicago, there are still sky-scrapers that have only DC!
Really? That's quite surprising. Which ones? How do they manage to keep any tenants, with special power requirements for everything from computers to air conditioning?
Presumably having DC wasn't a big deal back in the day-- resistive lighting, transformerless radios, gas fridges, toasters and percolators still being touted as "modern".
