Hi Jim
Okay.? Back to the beginning.? With reference to the drawing I
posted in the photo section.?
Correction 1: The two red marks to the left of the crossover move
to the right of the crossover..
Correction 2: at the top left hand corner of the drawing, switch
"Rail B" and "Rail A" so that they are consistent with the Main
Layout trackage, which is all fixed polarity, Rail A on the
"outside".? Note, it is shown as being driven from a PSX.
When the crossover turnouts are all aligned for 'straight
through', the trackage from L to Q will have the same polarity as
the Main Layout.
When the crossover turnouts are aligned to crossover (they will
all move together), the trackage from L to Q will have to have
reversed polarity, so that they are consistent with the polarity
of the turnouts.
That reversing of polarity is what I'm getting at in this thread;
as stated, I COULD simply throw a DPDT relay with the turnouts,
but that causes the usual power cycling for anything in the
staging yard due to the slow nature of large mechanical relays.
With the AR section(30' long) across the top, the entire staging
area cannot be driven by an Autoreverser as well, as we would
violate the "no Autoreversers Adjacent" rule.? Besides, the yard
will be one PSX section, the rest of the trackage in areas B and C
will be a second section; hence, the autoreversing needs to happen
BEFORE the PSX inputs.? See the drawing!
So I was seeking a way to use a solid state device to reverse the
staging area when I throw the crossovers.? I have now found a path
forward, I think, though I'm waiting for a response from the
designer for a couple of details.
I'm well aware of the evils of adjacent autoreversers, and
too-short sections.
Thanks
Blair
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On 2021-08-29 10:32, Jim Betz wrote:
Blair,
? OK, now that we have that sorted out ... the only other way I
see a problem is
if you have two different reversing sections -and- have them on
both sides of
the cross-over section.? Your cross-over section is very short
(compared to the
length of even a short train.? IF you have both 'sides' of the
cross-over section
being a reversing section - then you can have them fighting each
other (it's
more of a timing thing) because the wheels will close the gaps on
both sides of
the cross-over section and connect?everything up as one long piece
of track.
If you have two reversing sections connected to each other (even
if they are
only connected by the train) - sooner or later?(and usually
sooner) they will
end up both trying to "correct the short".? The?-best- result when
that
happens is that the train will stutter its way thru until?the
double reversing
clears - this could even mean you'd see the train?hesitate for
every car in the
train as it hits one or the other or both of those cross-over
gaps.
? Keep alives will keep the train moving forward and eventually it
will clear
and run smoothly - but it's pretty ugly to watch happening.?
Testing with
just an engine or any train short enough to fit entirely in the
cross-over
section will not demonstrate this undesirable phenomenon.
? You -may- be able to deal with this problem by setting up the
two
reversers to trip at a different timing (one longer than the
other) but
even then it may not be the final solution.? Sometimes, what we
think needs to be a reversing section - actually doesn't need to
be.
? In your case, you may be able to use a normal (non-reversing)
breaker for the "right side of the cross-overs" and a reversing
one
for the left side (including the cross-overs?).? I haven't gone
thru?
your track plan and worked out if this will work or not ... I'll
let you
do that.
? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?
? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? - Jim
P.S. Yes, I've seen this happen on a large layout where the
"non-clearing"
train was longer than the reversing section.? The trains
stuttering their
way thru this situation were in hidden staging and so the layout
owner
didn't realize why the stutter was happening.
P.P.S. I strongly recommend the use of PSX breakers and reversers
and
? ? ? ? ? would not do any layout with any other brand.? Amongst
other
? ? ? ? ? things they provide is the ability to set both the trip
current and the
? ? ? ? ? trip sensitivity (aka timing) with jumpers on the board.
