75647070   
   From: joekor@earthlink.net   
      
   On 9/7/2014 11:01 PM, Calvin Henry-Cotnam wrote:   
   > Joseph D. Korman (joekor@earthlink.net) said...   
   >>   
   >> On 9/1/2014 9:06 AM, Calvin Henry-Cotnam wrote:   
   >>>   
   >>> I am not aware of the details of NYC's subway signalling system, but I   
   >>> am with Toronto's, which was modelled after NYC's. I was making some   
   >>> assumptions that may be incorrect as Toronto's may vary from NYC's more   
   >>> than I had thought.   
   > [snip]   
   >>> I find it difficult to believe that without reverse signalling on a line,   
   >>> that there is not a final red-only signal where a turnback movement can   
   >>> be done to prevent this sort of thing from happening. If this is the case,   
   >>> this is a very MAJOR design flaw.   
   >>   
   >> Interesting point, but that would require a stop and stay signal at the   
   >> "wrong" end of every station.   
   >   
   > No it doesn't, from the Toronto perspective. Only the end of each place   
   > where wrong-way operation is possible needs such a signal. Hence, the   
   > point about most of Toronto's subway system being signalled for only one   
   > direction.   
   >   
      
   That's the point then, there are few places on the NYC subway that   
   reverse running is permitted and those points are protected.  In fact if   
   the interlockings are controlled from different towers, traffic   
   direction can't be changed unless there are no trains on the section and   
   both towers reverse the traffic in the correct order.  This mostly in   
   the river tunnels and third tracks.  I believe the four track IND Queens   
   line has one of the express tracks signaled in both directions at least   
   part of the way.   
      
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