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From: "Joe Mayer" jmayer AT insight DOT rr DOT com
Date: Wed, 24 Mar 2021 07:48:35 -0400
Subject: Re: (erielack) Switch Timer Locks
"Kent_Div_Board_3.jpg" - image/jpeg, 2592x1944 (24bit)

To clarify what I had posted earlier, the timers I was referring to did not
unlock a switch. The locations I referred to were spring switches on the
outbound end of passing sidings (the inbound ends of which were controlled
either by an operator or the DS). The timers involved were associated only
with the dwarf signal so the crew of the departing train knew if they could
depart right away, or if they had to wait for the timer. As the DS told me,
based on what he could see on his board, he couldn't even tell if the crew
used the timer- there was no indication on his board other than the WB home
signal at SC going red, but that would happen when the train pulled out onto
the main regardless.

In the case of the spring switches, the dwarfs/timers were tied into the
signaling system. For example, at SC activation dropped the WB SC home
signal to red (so the DS would not give permission if that would affect a WB
train). If there was any occupancy detected behind the switch (perhaps an
error or something else), the timer allowed for that to pass after the home
signal was red. But the switch was not "locked".

I know there are other situations where TPCs would be locked/unlocked by the
DS, but that was not the situation in the ABS territory on the Kent Div, at
the time. I have always liked the analogy of an ABS signal being an
"electric flagman". The DS had no control over an ABS signal, and in this
case had no electric indication of where trains were in the ABS territory
between control points. For example, if you look at the DS board for the
Kent Div. that was preserved and donated to the Marion Union Station Assoc.,
between the west end of the interlocking plant at SC, and the east end of
the Creston interlocking, the board show just a little dark square to
represent 9 miles of track, 5 EB ABS signals, 3 WB ABS signals, 3 TPCs
(Brickyard, Rittman, and Creston east), and the entire interlocking at
RU/Sterling. The only DS-controlled (movement or locking) turnouts in that
entire stretch would have been the ones INTO sidings at SC, which were lined
remotely by the DS in Marion. The TPCs, even at SC, simply had padlocks and
a call box.

For TPCs out in the ABS territory, I think the DS would be going by his
sheet as to giving permission for use. When a TPC was manually unlocked and
reversed, there was no signal in the direction of the movement, and I don't
think any protection on the receiving main other than the train's eventual
occupancy activating the ABS system. In other words, I'm not sure but it
doesn't sound to me like reversing the crossover itself was detected by the
ABS, or that simply reversing the crossover would drop any ABS signal to
red. Maybe someone knows more about that? The absence of signaling
explains the flagman at the return crossover when a detour caused wrong-way
operations.

Appreciate the great input.
Joe Mayer ELRRHS#702
Columbus (originally Wadsworth) OH


Kent_Div_Board_3.jpg

Image EXIF Data:
Image Creation Date   2011:02:06 17:00:10
Image Capture Date   2010:09:25 09:43:19
Image Digitized Date   2010:09:25 09:43:19
Make   Motorola
Model   MB200
X Resolution   72 Pixels/Inch
Y Resolution   72 Pixels/Inch
YCbCr Positioning   Center of Array
Exif Image Width   2592 pixels
Exif Image Height   1944 pixels
EXIF Version   0220
FlashPix Version   0100
ColorSpace   sRGB
Component Configuration   YCbCr


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