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Re: Trolley Poles and Pantographs
Author: Al Stangenberger
Date: 10-13-2015 - 17:54
At WRM, pantographs can only operate on tracks where the line department has inspected all the wire and approves it for pantograph use.
Trolley poles can operate on any track.
The main problem is at a switch where two tracks merge into one. All the wires are clamped into a trolley frog, which guides the trolley pole (with either a wheel or a slide) through the switch.
If a pantograph-equipped car is making a trailing (merging) move through such a switch and the trolley wire on the other track is lower than the wire the car is running on, then the end of the pantograph can hook over the other wire; when the hooked pantograph hits the trolley frog, the pan can be (1) torn apart, and/or (2) ripped off the roof of the car, and/or (3) the wire can be pulled down.
Differences in wire height at a trolley frog can be caused by differences in wire tension, or improper adjustment. Even a hot day can cause wire to sag enough to cause problems. Also, possibly the car's pantograph can lift the wire it is running on relative to the wire on the merging track, which can cause a snag.
Trolley poles can operate on any track.
The main problem is at a switch where two tracks merge into one. All the wires are clamped into a trolley frog, which guides the trolley pole (with either a wheel or a slide) through the switch.
If a pantograph-equipped car is making a trailing (merging) move through such a switch and the trolley wire on the other track is lower than the wire the car is running on, then the end of the pantograph can hook over the other wire; when the hooked pantograph hits the trolley frog, the pan can be (1) torn apart, and/or (2) ripped off the roof of the car, and/or (3) the wire can be pulled down.
Differences in wire height at a trolley frog can be caused by differences in wire tension, or improper adjustment. Even a hot day can cause wire to sag enough to cause problems. Also, possibly the car's pantograph can lift the wire it is running on relative to the wire on the merging track, which can cause a snag.
