[PRCo] Fw: Changing Track Switches
Phillip Clark Campbell
pcc_sr at yahoo.com
Mon Feb 28 10:52:31 EST 2011
Mr.Brannon
I wrote to Mr.Holland in San Francisco; included are
details of the system there.
Phil
----- Forwarded Message ----
From: "-> PRCo-- Holland James B.
To: Phillip Clark Campbell
Sent: Mon, February 27, 2011 9:26:58 PM
Subject: Re: Changing Track Switches
Good Morning, Phil -- Greetings, Herb!!,
The old system of Power On (toggle on many but not all PCCs)
or Coast through an overhead contactor can still be used with
both pans and // or poles; trains of cars using an overhead
collector then need special circuitry to prevent other cars
in the trains from resetting the turnout while the train passes
over same! Toronto, Boston, Shaker etc. did use
PCC trains; I am not familiar with their operations when
several poles on the train are raised.
To get around the special circuits needed for trains and
overhead contact activated turnouts, San Francisco Muni
surface electric turnouts are activated by 'track circuitry'
so any rail car can activate them. This is accompanied
by a 3-aspect signal, all 'white' lights:::
1. Vertical Bar for straight through
2. Angled or Horizontal Bar Pointing toward Diverge
3. Round White Light
Every "X"-seconds (5-10-seconds) either the Vertical or
Angled Bar display, never both. An operator will watch
this signal and move his train into the Track Block
immediately ahead of the turnout when he gets the correct
display -- Straight Through or Diverge. The point will set,
or remain set if already in the correct position, and the round
white light will display to show it is 'Locked.' The track
block is long enough so that the following truck enters before
the leading truck exits so any length train could pass through
while keeping the turnout locked. After the train leaves
the track block the round white light extinguishes and the
display of Vertical or Angle Bar resumes on timer.
Being a native of Pittsburgh I am keenly aware that use
of the sander is absolutely forbidden on the interurbans
because it 'possibly' breaks contact for the signaling
system. Several of 17-series Interurbans had brushes
mounted in the track brake to continually sweep the track
clear. A light outside the door side front windshield
revealed that this brush was activated. I, personally,
did not use sand at these track circuits. I mentioned
this problem to the Powers That Be but it was ignored.
Church and Duboce is where the J & N lrvs enter //
leave the subway; surface PCCs have a switch
immediately ahead of the portal to run around the
subway entrance to Market Street. The inbound
switch activates through the track circuits. I was
piloting a 2-car N-train OB, stopped behind a J in front
of me that was sitting on top of the special work for the
surface car diverge. As it was a rainy day, the
operator of a 2-car N train inbound used Sand all the
way across the intersection. He 'apparently'
received the light to confirm the point was set "But"
the sand apparently interrupted the circuit, the last
truck set the point for Market Street, so the tail of the
2-car train smashed into the side of the train ahead
of me with considerable force. Literally seconds
before that an Inspector was talking to the operator
using the operators left side window!
Muni never did issue a bulletin about sanding.
________________________________
________________________________
When operated by overhead contactor, this contactor
was placed "about 1-Car Length Plus 8-feet" ahead
of the point. This would prevent a following car from
resetting the point before the previous car cleared the
turnout. With the rear king pin being about 12-feet
in from the back, the last axle // wheel set is 9-feet
from the back so a following car can't possibly reset
the point for the leader. This can't happen with track
circuit switches because they lock in position --
if a following train enters the block before cleared then
the point remains set unless moved manually.
Subway turnouts are thrown by Dispatcher and or computer.
Bypass toggles are located at the turnout; if the turnout
is set incorrectly the operator stops the train at the toggle and
just reaches out his window to reset. But it is slow,
maybe a minute before a signal to proceed is obtained.
The Market street historic cars use a coil embedded in the
street at the turnout; pressing toggles inside activates the
coil when the car passes over it. I do not know the exact
details; sorry. To my knowledge, lrvs have not been
retrofitted with this system; they still use the track circuitry
on the surface.
________________________________
________________________________
Our TrolleyCoaches 'did' use "Selectric" turnouts with
several power turnouts on the system. "Selectric"
uses overhead contactors right at the points. They are
staggered so that they are activated one at a time for going
straight through. When a coach takes the 'diverge' both
contactors are hit at the same time, the points then set for
the turn, and immediately upon clearing the shoe activates
a lever to reset the points to straight. The Power
switches, like for PCCs, were too sensitive and activated
when not wanted. They are totally eliminated.
Many Selectrics are gone but replaced with a system using a
radio signal that work off the turn signal thus there are three
signals sent to an antenna loop on the curb side overhead
before the turnout: Right, Left, And Straight. If this
signal generator fails one can't set switches! Solar
flares are known to interrupt whole power grids, cell
phones, satellite transmissions, plane signals, etc. and
apparently these switches. We had a terrible time for a
month or two in the early 1990s with trolley poles going every
which direction but the correct. I detailed this in a report
with dates, times, places, even switches I was walking by
that activated without a coach in sight: Nothing in the
form of a bulletin from Muni. SEPTA is often referred
to as INEPTA but that Title Belongs to the San Francisco Muni!!
________________________________
________________________________
Nothing is ever clear cut. "In the Good 'Ol Days" of
overhead contactors, PRCo forbade operators using
the power pedal to set the points for diverge; it was
just the opposite in San Francisco. While the SF PCCs
had the toggle, most didn't work! On the Muni 1101s
(ex-SLPS cars) the track toggle actually engaged the drum
brakes "Only" if power was modestly applied; this drew
extra power through the contactor to set the point.
Using the track brake with power was Far More Effective~!!!
But the tens didn't have either mode for track setting;
Baby Tens did have toggle which usually didn't work so
one had to hit the power and brake after the point set~!!!
TTC and SLPS used "Necessity Action."
I do not know the exact details but 'apparently' action was
only needed to change the point; if it is set for the correct
direction nothing need be done.
Boston, DCT, and possibly Baltimore used "Another"
system. "All" turnouts were assigned Right and Left
"Legs" regardless of configuration:
* Coast thru contactor for Left LEG
* Power thru contactor for Right LEG
* Thus using "Power" on a left turnout one would go
straight through the Right "Leg."
* Using Power on a right turnout one would diverge to the right,
again the Right "Leg."
Nothing is standardized; each operator can claim unique
needs. There are probably dozens of other systems out there.
Jim
On 2011.02.27 9:15 PM, Phillip Clark Campbell wrote:
> Mr.Holland,
>
> Could you indicate how SF Muni lrvs operated track switches?
>
>
> Phil
>
>
>
> ----- Forwarded Message ----
> From: Herb Brannon <hrbran at cavtel.net>
> To: pittsburgh-railways at dementia.org
> Sent: Sun, February 27, 2011 8:29:37 PM
> Subject: [PRCo] Changing Track Switches
>
> As we know, PRCo/PATransit PCC car (using trolley poles)
operators changed automatic track switches by using the
"Track Switch" control on the dash. Now with the PAT
LRV cars (using pantographs) the routes and switches
are set by computer. This is also true in Cleveland on the
entire Red Line and the Green and Blue (former Shaker
Hgts Rapid) Lines as far East as E. 79th Station.
After that its back to old style manual control on the
Shaker lines. Now, SEPTA still uses trolley poles so the
"Track Switch" on the operators console is probably still
there and is used. On the other hand, most systems now
use pantographs. Like for instance MUNI in San Francisco
and I'm sure they have a lot of switches to go through.
My question is, how do the systems using pantograph
current collection change track switches? I know how it's
done in Cleveland, but not other places. Anyone know?
> --
> Herb Brannon
> In Cuyahoga Valley National Park
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