Over here in Chicago, they are rehabbing part of the “L” (or Elevated) tracks that carry people around the city. Last night on the news they were showing some of the ties that were being used for the rehab work. They are a recyclable “plastic composite” that is supposed to last 30 years or so. The ties “look” pretty strong, but that doesn’t mean anything. What I was wondering was:
Can those ties be used in mainline service on a freight railroad?
Do those ties have only “Light Rail” applications because they are not strong enough?
Are they being used by the larger railroads, and I have never heard about it?
Or, are wood and/or concrete ties the better option for mainline/freight railroad service?
(1) Plastic ties have “issues” like ballast degradation/ abrasion, resistance to fire/heat and what happens when placed in tension. (I’ve also heard that in curve applications, there is a different form of spike-kill [hole elongation] in certain kinds of plastic to deal with)
(2) Railroads have used plastic ties in limited numbers, usually on bridges in humid environments since the early 1990’s. Plastic timbers near the waterline on fenders and piles is becoming more common. Results have been mixed.
(3) 30 years huh?..Treated timber comes in at 35-50 years
Knowing how stupid and politically driven CTA has gotten, wonder if the ties were purchased for all the wrong reasons? If you want something to be bulletproof up on an exposed steel deck, why didn’t you use Azobe? (Oh yeah, CTA again [])
If I remember correctly, the loop portion at least of the CTA is open deck bridge. If that is true, might there be a benefit in the relative softness of the plastic ties on an open deck bridge??
Structurally-No…if there is some “noise dampening” benefit or other beneficial environmental issue out there, I’ve never seen, heard or read about it. (and the way the trade press loves to promote new ideas/ materials/ methods, it most likely would have gotten some play)
Maybe because there have been sooooo many past dissapointments with ties before (Cedrite, et al), the skepticism has crept in. [ and we all remember how long it took to get the concrete tie concept to where it is now - lots of early failures and lessons learned ]
I remember an article about a small short line a few years ago. The reporter asked the foreman how he knew which ties to replace. The foreman replied, " If I can remember installing the tie - then it is still good."
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