It used to be a common sight all over the city: “catenary,” the complex assembly of wires hanging over the street to power the streetcars. The complexity comes from the necessity of keeping the wires that actually provide power almost straight (so that the pantograph on the trolley is always touching them), which can be done only by bracing them and pulling them from all directions.
The only long sections of live street trackage left in Pittsburgh are Broadway in Beechview, seen here, and the Brown Line, which is not in regular service but takes the other lines over Mount Washington (via Warrington and Arlington Avenues) when the Transit Tunnel is closed for maintenance. There you can still examine live catenary and marvel at the geometry of it.
