From: stephen@sprunk.org   
      
   On 05-Oct-14 12:51, Overmod (Robert M. Ellsworth) wrote:   
   > Perhaps a more informative reference is the copy of the actual report   
   > that WNYC put up.  (This is a scribd document, so you may need to   
   > register with them and provide other material before you can download   
   > it):   
   >   
   > https://www.scribd.com/doc/241718975/NYC-Tunnels-Assessment-Report   
      
   Not interested in giving them a bunch of personal information just to   
   read what _should_ be a public document.   
      
   > The report notes that most of the damage is in the concrete bench   
   > walls, and chloride intrusion into the crushed-stone ballast.  Imho,   
   > the logical solution for the latter (as described in the report) is   
   > to use a modern 'top-down' track system as a replacement; this might   
   > also increase effective traffic throughput by allowing somewhat   
   > higher speed, especially in the 'outbound' North River Tunnel bore.   
      
   What does "top-down track system" mean?   
      
   I'm a bit surprised they're still using ties on ballast inside such   
   important and high-volume tunnels; direct fixation has been the norm for   
   decades, and from the sound of it, they wouldn't have had these problems.   
      
   S   
      
   --   
   Stephen Sprunk         "God does not play dice."  --Albert Einstein   
   CCIE #3723         "God is an inveterate gambler, and He throws the   
   K5SSS        dice at every possible opportunity." --Stephen Hawking   
      
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