The DC here in old Denver had much the same glass as the power system and some unique insulators used only on the DC. I have taken Denver's off the DC along with 135's 131's 134 dome embossed THE's and various 1871 patents. The one I remember most was the two 162 SS&CO's at the time Milholands hadn't seen one yet and I traded one to them.

Besides the Street Cars the old buildings elevators were DC voltage and that was still working here in the early 70's when we cut it all over and tore out the old wire.

The wire was a trip in itself it ranged from 4/0 solid, 300 solid, 500 solid, and 750 solid. When we were wrecking that stuff out all you could do was catch a span at a time, lay it on the ground and saw it up in pieces and throw it in the trucks. Most of this was tied in with #2 HD Copper on cable type porcelain insulators. The glass was used on buildings and the smaller stuff to the street cars. A lot of the early street car stuff had been taken over earlier, cut over to AC and used for the incandescent street lights..

(text and photo courtesy Larry Volmer - used with permission)