N&W CPL signals

[nw-mailing-list at nwhs.org]

Well then, that explains why I have never run across one!
   
  Ben Blevins
  

nw-mailing-list at nwhs.org wrote:
            Scribit Bennoczyk Blevinoshevsky:
   
  >>
  I have been searching for one of these myself for 15 years and have yet to run across one.
  <<
   
  Ben,
   
  You are diggin' in the wrong place, Sonny !  There weren't any on the Bristol Line.  I don't recall any even at Radford.  
   
  In my time (which goes back to 1964,) the first PL dwarf signal east of Bristol was at WB, West Roanoke.  Here's a picture of it, attached.  The view looks east.
   
  There were a bunch of PL dwarfs at Randolph Street.
   
  Prior to CTC, where there were "middle sidings" in double track automatic block territory, PL dwarfs were used at the ends of the middle tracks to govern pull-out movements.  Here is a portion of Time Table Special Instruction 103(a) from Radford Div. TT No. 3, effective July 19, 1931:
   
  "Position light dwarf signals controlling pull-out movement through trailing point spring switches at east end of Dry Branch middle track, and at the east end of Lurich middle track, indicate simply the position of the swtich and the occupancy of the main line block back of the switch and when in stop position may be passed protecting as per Rule No. 812."
   
  Explanation:  Your train is in the middle track and wants to pull out.  Obviously you don't want to pull out while a train running with the current of traffic on the main track is approaching.  There would be a nasty side collision.  So... these dwarfs were arranged to display a proceed indication ONLY when (1) the switch was properly lined for movement and (2) when no train was approaching in the signal block on the main track.
   
  Now, there's another item in this same Special Instruction that apparently refers to situations where display of a favorable aspect on the Position Light dwarf signal was not governed by occupancy of the signal block on the main track, and where the crew had to call the operator to insure that no train was approaching:  
   
   "Position light dwarf signals governing the pull-out movement through the trailing point switches at the west end of Vicker westward passing track, west end of Walton-Pepper middle track, at west end of Lurich middle track. and at each end of Blake middle track, must be regarded as stop and stay signals and when in stop position must not be passed without permission from the interlocking plant operator in addition to protection as required by Rule No. 812."
   
  Explanation:  Vicker/Walton and Lurich and Blake all had interlockings and towers.  The railroad had saved a few bucks by not providing wiring to govern display of the pull-out dwarfs over the track relay of the main track.  Instead, one called the operator at Walton, Lurich or Blake before pulling out, to determine if any train was approaching.  The operator was already there, so the railroad used him to save a few bucks in wiring.  That's my read.
   
  If you really want to fry your brain, note the different verbs used in the two cited Special Instructions.  In the first case (where there no operator involved,) the PL dwarfs "control."  In the second case (where there is an operator involved,) the signals "govern."  Is that choice of words intentional, or merely coincidental?  On a really big road like the PRR or the NYC, those would have been technical terms with technical meanings and those who wrote Special Instructions would have been aware of how to use them properly.  But on the N&W in 1931, the words were probably non-technical and their use was probably coincidental.
   
  Again, let me emphasize that dwarfs were not used because of any clearance situation.  They were used on tracks where a long "preview" or range was not needed because trains would only be approaching at "Low Restricted Speed."
   
  -- abram burnett,
        Curmudgeon of the Second Order
           (subordinate only to Prime Curmudgeon "EdK")




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