The tram system that I used (borrowed) used Phillystran for it's tram wires.
I've never used Philly for tram material and I know it's lightweight and
has the required strength to handle the job. However, having worked with the
stuff for over 20 years, my concern would be its lack of resistance to
abrasion. Pulleys can get stuck (no rotation) and could really chew up a
cable in a hurry, and just the general run up and down would eventually abrade
the covering. Plus the stuff is expensive. YMMV.
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