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| Re: Why The R-44's Rusted Out at the Frame (887778) | |||
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Re: Why The R-44's Rusted Out at the Frame |
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Posted by Widecab5 on Mon Jan 18 11:28:26 2010, in response to Re: R44's soon to be swimming with the fish, posted by Vacuum Tube on Sun Jan 17 12:01:45 2010. On the R-44's the framing is all carbon steel with a stainless skin (one reason for their being overweight). Why is unclear but two most likely explanations are cost to SLC-GSI or that metal technologies had not yet developed (at least as of 1968) to allow the stainless steel framing that was needed. Whatever, the issue was addressed before Pullman-Standard began construction of the R-46's in 1974 and they were most definitely built with stainless steel underframing.The mid-body "blue belly band" on the R-44 was originally a thin sheet metal bridge between the two flash welded sections of stainless steel skin (upper and lower). This was done because during their construction the R-44 bodies were over the prescribed weight and this was a seemingly non-controversial (and desperate) way to shed pounds. Then came the grime, then the graffiti, and with it in 1982 came acid baths. Not only were the bodies scrubbed to base skin, but the bare sheet metal was eventually exposed to the acids. As it hit pre-existing rust pockets on the sheet metal, these were eventually eaten away and the subsequent acids released into the underlying frame members. Moreover, as each train was bathed repeatedly in the acids, and as the fluid more easily invaded the underframing each time, it would run down the verticals to the base, and pool at the sill members until it either evaporated (dried) or was absorbed into the steel (and that was originally very robust steel). As the acid and bare steel co-mingles, the massy goo that results (and is perpetually developing once set in motion) has been gradually decomposing the steel framing from within and pushing against the visible stainless steel skin without like a fist. This threatens the original SLC-GSI flash welds on the back side. It produces those noticeable "dimples" at the sill line of the R-44's (and formerly of the Redbirds and carbon steel SMEE's before them). When the R-44's went to M-K, M-K alerted NYCTA to the issue but TA knew about it long before. M-K recommended a stainless steel bridge sheet to replace the original sheet metal, weight considerations aside, but (apparently because the powers that be felt this too costly given that the R-44's were already too far gone and would only be needed for about another 15 years at most [until approx. 2005]) this was nixed and the sheet metal bridges salvaged or replaced with like materials. Dimples = Rot. Can't stop it. Can't cure it unless you can replace all the underlying steel. The Staten Island R-44's have the same construction, but because they were not bathed in acid over and over (not as much graffiti?) do not exhibit the same kind of inherent deterioration. They are rusted, however, in large part because of exposure to the natural elements of their operating environment for 35 years. As a temporary measure (5-10 years?), CI Shops is cutting vent holes into the body skin beneath the door thresholds and covering them with a screen. The hope is to allow air to circulate within the framing overlays (which are in fair shape at best for their age and construction) to prevent undercar moisture (in this case from rain, snow and frost) from washing at the aging steel any further. You might notice these little screens on the rehabbed SIR R-44's. And (with apologies to Paul Harvey) now you know the rest of the story. Regards, George Chiasson Jr. (Widecab5@aol.com) |
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