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Re: TriMet Time Lapse Video of Catenary Weights During Heat Wave
Author: Dr Zarkoff
Date: 07-09-2021 - 10:53
> When rail expands length-wise, are angle bar bolts loose enough so that the gap between rail sections can open and close?
Up to a certain amount of expansion and contraction, yes. However, sun kinks can occur in jointed track.
> 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 axle loadings of US railroad equipment make expansion joints a maintenance headache, so while they are used in some bridges, like the Suisun Bay Bridge on the SP/UP, they tend not to be used in CWR, choosing instead to use an "equalization temperature". The AT&SF used to equalize and anchor the CWR between Stockton and Richmond to 100/110 degrees, and east of Stockton, to 120 degrees. On hot days, you could see the rails becoming "snaky", as one district M/W supervisor explained to me, i.e. as you sighted down the length of a rail head, it became rather wiggly looking on hot days..
Up to a certain amount of expansion and contraction, yes. However, sun kinks can occur in jointed track.
> 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 axle loadings of US railroad equipment make expansion joints a maintenance headache, so while they are used in some bridges, like the Suisun Bay Bridge on the SP/UP, they tend not to be used in CWR, choosing instead to use an "equalization temperature". The AT&SF used to equalize and anchor the CWR between Stockton and Richmond to 100/110 degrees, and east of Stockton, to 120 degrees. On hot days, you could see the rails becoming "snaky", as one district M/W supervisor explained to me, i.e. as you sighted down the length of a rail head, it became rather wiggly looking on hot days..
