I don't know what's dopier -- MBTA not being able to fabricate tieplating to gauge, or the RT&S story -- with the byline of Managing Editor -- calling it "ties too close together".
Another consultant without much of a clue, too. How hard is it to use a calibrated gage to measure distance between lateral faces of tieplates? Evidently too hard for Bostonians...
Measure once, measure twice...Thimk!
From https://www.boston25news.com/news/local/most-new-mbta-green-line-tracks-need-be-fixed-after-construction-oversight-failures/4SIYVTSVCVCQPO7EXDHJ27PCMY/:
"The project’s construction standards require a width between the rails of between 56 and seven-sixteenth inches and 56 and nine-sixteenth inches, Eng said Thursday. The threshold for slow zones is lower: anything below 56 and one-eighth inches is so narrow that it’s unsafe to run trains at full speed."
That strikes me as an extremely tight construction tolerance for something that involves pounding spikes or drilling screws into hard wood. It may be possible to exceed that tolerance even if you lay the plate in the correct place prior to fastening if down - the holes for the spikes or screws have to be bigger than the spike or screw itself. If each one is bigger by 1/16", then the two sides together have 1/8" of slop right there.
They are apparently making plans to re-gauge most of the newly-constructed track. Gauging is necessary sometimes but isn't good for the ties' lifespan. While they can probably get it so that the average is correctly centered around 56 1/2", I wonder how much of it will still be outside the construction spec when they're done.
Also note that the serviceability tolerance (gauge >= 56 1/8") is more restrictive than FRA standards for 160 MPH high-speed rail. I vaguely seem to recall that when the Type 8 cars from Breda, which were the first to have a (partial) low floor, first showed up on the property in the early 2000's and we're falling off the track with alarming regularity, the T had to repair quite a few sections of track. I believe a stub axle on a low-floor LRV can be more sensitive to gauge issues than when the two wheels are attached to a single axle. Whether the T's maintenance standards were lower than the product specs given to Breda, or whether they just hadn't been maintaining everything to their standards, or whether they just found it easier to change the track than to get Breda to build cars that could actually meet the spec, I don't know.
None of this is intended to excuse the contractor, but at the same time, I do wonder why the T spec'ed timber ties at all if they wanted such tight tolerances.
Dan
Note: something got fat-fingered here. At 58 1/8" the wheels would be falling-in and would not even be FRA Cls. 1 (10 mph).
Otherwise to Dan's commentary. Somebody needs a new track gage tool?
mudchicken Note: something got fat-fingered here. At 58 1/8" the wheels would be falling-in and would not even be FRA Cls. 1 (10 mph). Otherwise to Dan's commentary. Somebody needs a new track gage tool?
Yes, the fat fingers were mine. Sorry. I will correct my original post to say that 56 1/8" is the limit for speed restrictions (according to the article).
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