[PRCo] Re: Derail

[fwschneider at comcast.net]

My mistake.   Another note today will explain why I'm not totally tuned in to the world, Phil.  
My humble apologies.

Fred

-------------- Original message -------------- 
From: Phillip Clark Campbell <pcc_sr at yahoo.com> 

> My name is Phil isn't it. 
> 
> 
> ----- Original Message ---- 
> From: "fwschneider at comcast.net" 
> To: pittsburgh-railways at dementia.org 
> Sent: Thursday, September 27, 2007 1:49:10 PM 
> Subject: [PRCo] Re: Derail 
> 
> Ah, but some, like the one on Fineview were simply sprung to restore to the 
> derail position after the car went through it. Such derails were used to 
> prevent cars from rolling backwards. 
> I thought the one at Tunnel was a timed derail using two contactors but Herb 
> appears to have corrected that false impression. 
> -------------- Original message -------------- 
> From: "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" 
> > To: 
> > 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 
> > 
> > 
> 
> 
> 
> 
> 
> 
> 
> 
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