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| Question on Platform Edges in Past Subway Construction - IRT After 1920's (1385460) | |||
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Question on Platform Edges in Past Subway Construction - IRT After 1920's |
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Posted by W.B. on Sat Feb 13 16:50:14 2016 Looking at the various articles on this site, plus having seen some Engineering Records (pre-1917 merger with Engineering News to form Engineering News-Record) and other publications, I've noticed that from the time of the 1904 opening of the first IRT subway to the mid-1920's, the specification for the outermost platform edge positioning in relation to the track center line on that company's tracks was 4' 9½" from the concrete/steel platform shell, and 4' 7¾" from the tip of the rubbing board (meaning the width was a mere 1¾" - less than the 2" on BRT/BMT platforms constructed during the Dual Contracts which specified 5' 4" for the former measurement and 5' 2" for the latter). I presume it was when the Times Square then-terminus of the Flushing line was built for opening in 1927 that the rubbing board width was expanded; the question is by how much, and how did the concrete/steel platform foundation's measurements change - to 4' 11"? 4' 11¼"? I know this modified spec (which would have dovetailed with the point at which the IND was being planned and built) was used on the sections of older platforms that were extended over a 20-year period after World War II, as well as the express platforms of the 59th Street station of the IRT Lexington Avenue line as opened in 1962. (I also know some of that particular line's platforms were built to BRT standard concrete/steel distances of 5' 4" to track center because of the ambiguity at the outset of who would operate the line, then a 6½" plate added after it was decided the IRT would.) |
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