 |
Re: Trolley Poles and Pantographs
Author: mook
Date: 10-13-2015 - 20:41
Wire setup was probably cheaper. IIRC none of the PE photos I've seen show any catenary - all simple suspension, which is cheap and works fine with poles at reasonable speeds. Except for the 50-60 mph San Bernardino line PE seldom exceeded 30-35 mph, maybe 40 in really open spots.
Pans seem to need (at least by modern light rail standards) full catenary wire suspension at higher speeds (above 30 mph or so). Simple suspension is used mostly in downtown areas where speeds are low.
Pans do have an operating advantage in that they're bidirectional - no need to go outside and change poles at the end of the line. Muni got around that on most of their 1950s-60s streetcar lines by having a loop at each end of the line, though they needed a front pole and backup controller (under the back seat) on the single-end PCCs for yard use, so they could be used on the J line with its end-of-line wye, and so they could be short-turned at various points along the lines with wyes in a side street. The entire Muni had simple wire suspension and used poles until light rail cars came along.
Pans seem to need (at least by modern light rail standards) full catenary wire suspension at higher speeds (above 30 mph or so). Simple suspension is used mostly in downtown areas where speeds are low.
Pans do have an operating advantage in that they're bidirectional - no need to go outside and change poles at the end of the line. Muni got around that on most of their 1950s-60s streetcar lines by having a loop at each end of the line, though they needed a front pole and backup controller (under the back seat) on the single-end PCCs for yard use, so they could be used on the J line with its end-of-line wye, and so they could be short-turned at various points along the lines with wyes in a side street. The entire Muni had simple wire suspension and used poles until light rail cars came along.
