From: stephen@sprunk.org   
      
   On 28-Dec-15 15:38, hancock4@bbs.cpcn.com wrote:   
   > Stephen Sprunk wrote:   
   >> On 27-Dec-15 20:32, hancock4 wrote:   
   >>> I believe much of the Long Island Rail Road and ex PRR SEPTA   
   >>> lines still use the amber position light signals, though upgrades   
   >>> may have eliminated some signals.  FWIW, relatively new pictures   
   >>> on nycsubway of the LIRR trunk line show signal bridges with PRR   
   >>> style signals.   
   >>   
   >> Most RRs upgrade signals only when they fail, and that won't   
   >> happen very often for position-light signals; they use long-life,   
   >> hard-duty bulbs for obvious reasons.   
   >   
   > I believe sometimes there is a economic motivation even if the   
   > existing signal system is working as expected.  I believe old   
   > systems with relay logic were still labor intensive and modern   
   > systems are more reliable and automated.  Further, a replacement   
   > system may increase track capacity by allowing higher speeds and/or   
   > more trains.   
   >   
   > But also, on some old railroads the signal systems might be 75 y/o   
   > and no longer reliable.  The IND in NYC is supposedly a challenge   
   > since it has many miles of original 1930s wiring and relays. (I   
   > believe some of the money intended for the Second Ave Subway in the   
   > 1950s was spent instead of redoing the then 50 y/o IRT signals to   
   > modernize them and increase capacity; which was probably a   
   > worthwhile expenditure).   
      
   Changing the color(s) of the signal heads and changing the logic that   
   drives them are (or at least should be) completely separate projects.   
      
   One of the things that's frustrating about Amtrak is that they tie   
   numerous projects together into one mega-project, then complain they   
   don't have the funding and do nothing, whereas they _do_ have funding   
   for one project at a time, and its benefits would fund the rest.   
      
   >> OTOH, what all is needed to do a conversion?  Remove the center   
   >> bulb and block the hole, change two outer lenses from amber to   
   >> red, two from amber to green, two from amber to lunar white, and   
   >> then what?  That seems simple (and cheap) enough to just all the   
   >> rest at once.   
   >   
   > I believe there are modfications to relay controls, perhaps the   
   > wiring, not just the signal head.   
      
   The _only_ difference between Amtrak color position light aspects and   
   PRR position light aspects are the colors themselves and the missing   
   center lamp.  IOW, there is no change outside the signal head itself.   
      
   > For example, at one NEC location, I noticed that the hardware   
   > holding up a signal was badly corroded. It appeared when they went to   
   > color they replaced all the hardware and put it an all new signal   
   > head.   
      
   Two unrelated projects that happened to be done at the same time.   
      
   There _are_ cost savings from only visiting a site once, e.g. one visit   
   costs $25k but two visits cost $15k each.  But if your complaint is you   
   can't afford the $25k, then pay the $15k and let the savings from having   
   done that work sooner pay for the second $15k visit later.   
      
   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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