Street car rail weight - Trains Magazine
I suspect that most of the first generation of streetcar and interurban lines were significantly undercapitalized and one of the one many places where they did things on-the-cheap was rail. The entrepreneurs who built these lines probably used the lowest weight rail they could get away with, and maybe they figured that with traffic growth they might be able to afford a better and more substantial track structure later. Well as we all know, Walter Chrysler, Henry Ford, and Alfred Sloan came along and changed American transportation habits, much to the detriment of the electric traction industry.
For those lines that survived a shrinking traffic base, the Great Depression, and World War 2, by the time 1946 rolled-around the physical plant was shot and there was no money in the till to fix the track.
Fast forward now to 1980. I was visiting my old residential neighborhood in the Mission District of San Francisco whereupon I came across the rebuilding underway of the J-Church streetcar line. The rail being pulled out was so thin, corroded, and worn, I swear to God a 6-year old could have used that iron as a toothpick. As for the crossties, they looked so pathetic that I bet the track kept gauge only out of force-of-habit!
As I recall, the San Francisco Municipal Railway was replacing what appeared to be the original track structure with concrete ties and the heaviest rail I'd ever seen being laid in North America. Sure, it was overkill and the up-front costs of that rehabilitation project must have been enormous, but I bet the track structure (barring any catastrophic earthquakes) will last a hundred years, or more.
I suppose it's no wonder then that Portland, Ore. adopted elements of the San Francisco experience as well as the Austrian, Belgian, Czech, Danish, and German practices mentioned above by "daveklepper."
