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Re: TriMet Time Lapse Video of Catenary Weights During Heat Wave
Author: FUD
Date: 07-08-2021 - 20:01
Some railroads in Europe use expansion joints to allow for expansion/contraction of welded rails where the annual temperature range is wide. Also used where the tracks cross major bridges.
The constant-tension thing for wires isn't new. Nearly every electric railroad that runs at more than ordinary street speeds using catenary has it. Sacramento's weights hit the ground at about 110F, and there is inevitably a pull-down if they try to keep operating after that. I've wondered if an adaptation to climate change might be to bore a hole at the bases of the poles for the weights to descend further into. FWIW, copper expands and contracts more with temp than steel does.
The constant-tension thing for wires isn't new. Nearly every electric railroad that runs at more than ordinary street speeds using catenary has it. Sacramento's weights hit the ground at about 110F, and there is inevitably a pull-down if they try to keep operating after that. I've wondered if an adaptation to climate change might be to bore a hole at the bases of the poles for the weights to descend further into. FWIW, copper expands and contracts more with temp than steel does.
