[PRCo] Re: Derail

[Boris Cefer]

Yes, Fineview had a derail on Carrie Way. An another derail that "I 
remember" was on 5-Spring Hill near the foot of Itin Street.
Thanks for the description! I haven't heard it yet.

Boris

----- Original Message ----- 
From: "Phillip Clark Campbell" <pcc_sr at yahoo.com>
To: <pittsburgh-railways at dementia.org>
Sent: Wednesday, September 26, 2007 9:10 PM
Subject: [PRCo] Re: Derail


> The derail worked similarly to any track switch in that it was controlled 
> by the operator through a contactor in the overhead.   For Prc it was 
> coast through the contactor to set/maintain the straight through or draw 
> current through the contactor to set/maintain a diverge movement at 
> turnouts on the system.
>
> The Derail was a special situation - it was a diverge movement to derail 
> and a straight through movement into the tunnel when set properly but it 
> was necessary to draw current through the contactor to set for this 
> straight through movement.    This was a spot for crew changes wasn't it 
> and if a car rolled when the operator was not present it would coast under 
> the contactor and not set the point to travel into the tunnel - the car 
> would technically derail but there was a block there to prevent this and 
> stop the car instead.
>
> On the old cars the operator could use a combination of power and brake 
> simultaneously to draw the current through the contactor; on Prc Pccs 
> there was a toggle on the dash which drew current through a resistor to 
> set points for diverge.  It was forbidden on Prc Pccs to set points by 
> using the power pedal.   Thus the operator had to take specific action to 
> set the point straight at the derail.
>
> The derail had a time delay feature as well  --  the track point would not 
> set immediately upon passage through the contactor.  This could possibly 
> catch a car with slack brakes.
>
> After the car passes through the derail successfully there is a simple 
> contactor in the overhead (like those used to activate Nachod signals) 
> that resets the point for the derail position.  It doesn't matter if the 
> car coasts or draws power through this contactor.
>
> This junction and derail were interlocked with outbound movements.  If a 
> 44 or 48 car had already set its point and proceeded through the turnout 
> it prevented operation of the interurban derail until the 44 car cleared.
>
> As originally built the derail was a RR point and possibly operated by the 
> man in the tower  --  but this would not catch equipment with slack brakes 
> would it.  Don't remember when Prc first used electric turnouts; believe 
> it was in the 1920s but don't have my notes.
>
> I have often wondered why there weren't derails in the outbound tracks as 
> well since crew changes happened in this direction; a car could roll 
> backward into the tunnel.    Such a derail is a simple sprung point.
>
> Prc had derails at other locations and some reverse derails for cars that 
> would roll backward.  There were derails on the 46 aka 49 on New Arlington 
> but being single track they have to be for rollbacks in one direction. 
> Didn't the 21 Fineview also have derails to prevent rollbacks?
>
> Phil