[PRCo] Re: WP signals

[Fred Schneider]

I am going to butt in here Phil.

We did have the technology to develop shunts that dropped in when a bulb burnt out.   If you were ever to look at the Lancaster (PA) Birney car that is preserved in Manheim, PA, it is a perfect example.   There is a whole block of shunting resistors at one end of the car.   If any light bulb burns out, one of those resistors will take its place.   

Why?   Because in a 30 foot long car, there is only one string of light bulbs down the middle of the car.   Otherwise, the entire car would go dark if a bulb burnt out.   It actually has two strings ... five bulbs to light the interior on one string.   The other string consists of two bulbs in shades on each platform and the headlight.   Of course there are ten resistors that click in if a bulb goes burns out.   

The Pittsburgh 1700s had extra bulbs in the door engine compartments.   The only problem with that is that the guys at PTM never look to see that something is burned out until two go out, then the voltage goes up and the whole friggen string goes out.   

I would not be surprised that Ed had the right suggestion that the signals on West Penn had a cutout resistor so that all bulbs didn't go out if one burnt out.   But today, I don't know who you would ask.  Remember, its been 58 years since the last West Penn car ran.   Maybe we have a wiring blue print in the library that John Wilkins saved and then maybe we don't.


On Nov 24, 2010, at 12:40 PM, Phillip Clark Campbell wrote:

> 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.'
> 
> 
> 
> 
> 
>