From: jgrove24@hotmail.com   
      
   On Sunday, October 5, 2014 2:47:17 PM UTC-5, Adam H. Kerman wrote:   
      
      
   > >What does "top-down track system" mean?   
   >    
   >    
   >    
   > In direct fixation, it means top of rail and gauge are established to the   
   >    
   > specification, then the fasteners are attached, then the concrete is placed   
   >    
   > last. That really makes a lot of sense, because there's just the one step   
   >    
   > at which things are calibrated. Bottom up requires a lot more calibration.   
      
   UP is getting the new track installed on the Metra UP-N line bridge   
   replacement project. There's some long pieces of welded rail sitting on the   
   gravel and stocks of concrete ties at the mini yard off Elston/North av. I   
   still think building a new rail    
   viaduct for this was a waste of money.   
      
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