[PRCo] Re: WP signals

[Dwight Long]

Phil

Perhaps.  I will leave it to the electricians or electrical engineers to sort that one out!

Dwight

  ----- Original Message ----- 
  From: Phillip Clark Campbell 
  To: pittsburgh-railways at dementia.org 
  Sent: Wednesday, 24 November, 2010 12:40
  Subject: [PRCo] Re: WP signals


  Mr.Long;
  Could the shunt contain a dropping resistor?  The books say
  6 or 7 bulbs between sidings.  With 7-bulbs on 700-volts, one
  missing would be 117-volts/bulb.  If there were only 6-bulbs
  between sidings, each would carry 117-v until one goes missing;
  then there is 140-v on each bulb.  This without a resistor in the
  shunt of course.



   Phil
  Without  a   'coast'   but  not  a   'cause.'





  ________________________________
  From: Dwight Long <dwightlong at verizon.net>
  To: pittsburgh-railways at dementia.org
  Sent: Wed, November 24, 2010 12:05:19 PM
  Subject: [PRCo] Re: WP signals

  Ed

  That would make sense and would be a good safety feature.  It would, however, 
  require vigilance on the part of the "signal maintainer" to replace burnt out 
  bulbs because it would increase the strain on the remaining lit ones 
  significantly.

  Dwight

    ----- Original Message ----- 
    From: Edward H. Lybarger 
    To: pittsburgh-railways at dementia.org 
    Sent: Wednesday, 24 November, 2010 08:43
    Subject: [PRCo] Re: WP signals


    The left-hand operation was determined more by geography than anything else.
    If it was safer to go left, they did.  Many of the LH sidings were along
    highways and at the foot of grades where there could be derailment issues.

    I suspect that WP used signal bulbs with a shunt that allowed a complete
    circuit to be maintained if a bulb burned out, just like the PCC cars do.
    They could not afford to have a dark block, and as Dwight says, there were
    very few accidents.

    Ed

    -----Original Message-----
    From: pittsburgh-railways-bounce at lists.dementia.org
    [mailto:pittsburgh-railways-bounce at lists.dementia.org] On Behalf Of Dwight
    Long
    Sent: Tuesday, November 23, 2010 8:38 PM
    To: pittsburgh-railways at dementia.org
    Subject: [PRCo] Re: WP signals

    Phil

    I don't know what the frame of reference was for this post, but I can add
    this:

    Yes, there were two "paddle" switches in the West Penn system--one turned
    off the lights in the section just vacated and the other turned them on in
    the section ahead. West Penn often operated their spring switch-equipped
    crossing sidings left-handed so that the motormen could lean out the door
    and throw these switches when located in the space  between the tracks.
    This, however, was not universally true.

    The system over the years presented very few problems from "signal failure."
    But it was not a fail safe system.  Such a system would have had the lights
    on constantly except when the block was occupied.  In that manner, signal
    lights out would have meant that a car could not enter the block.

    The biggest problem was that the lights were connected in series, just like
    old fashioned Christmas tree lamps, and if one went out, all did.  However,
    the most likely time for one to fail was when first switched on from cold,
    and motormen were not permitted to pass into a non-lit section without
    dispatcher authority. The problem was mitigated somewhat by running the
    voltage at less than for what the lamps were rated.

    Second sections were rare on WP, but one could follow into the block on its
    leader, maintaining visual contact but with sufficient distance to stop if
    the leader did.  The alternative, for a not-too-close following section, or
    an excursion car, was to wait for the leader to vacate the block ahead
    (lights out!) and then proceed as normal, lighting up the block before
    entry.

    There were intermediate lights at places such as curves with limited
    visibility, etc, but this of course did not help the spacing problem with
    following moves, just alerted the motorman if an opposing car had ignored
    the crossing point and entered the block.

    Human error as well as electrical error was always a potential in a system
    as primitive as this.  However, on the up side, WP motormen were very
    professional, conscientious, and alert to their surroundings, the schedules
    and normal crossing points, and the like.  Such a system would probably be
    asking for a collision with today's far less well trained and disciplined
    work force.

    What prompted this enquiry?

    Dwight
      ----- Original Message -----
      From: Phillip Clark Campbell
      To: pittsburgh-railways at dementia.org
      Sent: Tuesday, 23 November, 2010 19:59
      Subject: [PRCo] WP signals


      I assume that releasing the signals behind at a siding and
      activating the signals ahead were separate functions.  The
      drawing suggests they 'may' work simultaneously.  This is
      in regards to the manual signals.
      With 30-60 min headways there isn't much problem with
      following cars, just opposing.  Did this system of signals
      present many problems?  Did WP have cornfield meets
      from signal failure?

      How were signals handled when a second section was added
      to a schedule?  Did both cars occupy the single track at the
      same time?  Spacing could be a problem with all the curves.
      I could see the first car forgetting about the second section
      then shutting down the signals at the next siding.  This could
      allow an opposing car to meet the second section on single
      track.


       Phil
      Without  a   'coast'   but  not  a   'cause.'