Well its been a year since I posted a problem with the MRC Auto reverser on a balloon track. Since then I have changed the layout to leave only one reverse loop or balloon track and a slight problem still exists… The loco enters the loop over the Auto reverser(Gap A) and everything is fine, it proceeds around the loop but when the loco goes over the gap (Gap B) to leave , it stops… If I enter the loop the opposite direction it enters over the gap (Gap B) and proceeds around the loop over the AR leaving the loop(Gap A) theres no problem… I have tried 3 AR’s , 2 of which are brand new! I have sent the control unit back to the manufacturer for testing as we thought there was a problem with voltage supplied to the track and they say all is good! I also send a diagram of the layout to the manufacterer and they see no problems. Should I look at stay alive capacitors? Or just be happy with a loop around with no capability of reversing directions?
It might help if you post the diagram here. You look fairly new so you will need a photo hosting site for the photo if not aware.
Rich
Does this happen with multiple locos? When you approach gap B the rails are out of phase and the reverser corrects that problem. If you run a loco over B and bring the rails in phase, and then place another loco in the loop and run it through B (with the rails already in phase) does the loco still stop? Trying to see if other factors are in play.
which model AR and how it is wired
I had a similar problem at one time, trains went thru one direction OK but not the other. Turns out one of the feeders for one rail in the reverse loop got connected to the ‘regular’ wiring for the rest of the layout in error. Going one way, the polarity matched, the other, it didn’t. I’d suggest going over or even re-doing all your wiring relating to the reverse loop to be sure something like that isn’t happening.
Similarly, it could be one insulated rail joiner has gone bad, or a rail gap has somehow closed together over time, so one rail is no longer insulated. It would have a similar result, trains would only work one direction.
In either case, it’s possible to have a trickle of power that’s not enough to trip the short circuit detector, but is enough to mess up the reverser.
Hello All,
I don’t know if this has been asked/answered…
Are you running DC or DCC?
Hope this helps.
Agree with Stix, given that you have tried multiple AR’s, possibility of other causes increases.
wouldn’t there be a short across the closed gap when the section matches the polarity at the other gap?
so the problem is only leaving the loop at gap B?
is there a short, either from the booster or the AR?
how far apart are the gaps at both ends from the AR connection to the mainline?
He is running a MRC Prodigy Advanced.
Currently MRC only lists one Reversing Unit and there are only 4 wires to deal with.
As I understand it, MRC has checked his Prodigy, looked at his track plan and 3 AR’s don’t work in one direction on the reversing loop.
Seems unlikely that MRC doesn’t know how to make an AR compatible with the Prodigy. The unidrectional operation of the AR ought to be telling us something, but I don’t know what. Maybe Stix nailed it.
A track diagram would help. If it’s a diagonal cutoff type of reverse loop, is the train entirely within the reversing section before crossing the exit gaps? That would definitely cause an issue where the train can enter the loop either way, but fail to exit cleanly.
If it’s a loop in the sense that the diverging leg of a turnout comes back to the straight leg, it pretty much has to have the whole train fit inside the reverse section, or the engine would hit the tail end. However - what brand of turnout is used here?
When the train halts existing the loop - does the breaker in the main system trip? This could indicate something like the issue of one feeder crossed, or a bad gap, or simply inadequate feeders in the reverse section.
–Randy
Are the gaps in the rails straight across from each other?
if it is adjacent to a gap, either it always causes a short when a loco bridges the gap it’s adjacent to or the loco stops on it when approaching from the opposite direction, not at the gap.
does “goes over the gap” mean
- when metal wheel bridges the gap
- the truck/wheels are just across the gap with the gap under the loco
what happens if the reversing section turnout frog and diverging rail up to the gap are powered and the turnout is not thrown correctly when exiting the reversing section
How are the points being set? And how are the point rails powered? I mean, that may cause a difference between entering and exiting scenarios.
Also, I notice in that AD520 manual, the bus connection is not to the main rails, but connected past the turnout toward the loop. This does not jive, to me, not quite sure why. Just not consistent between the entrance and the exit.
It’s essentially the same thing. The main would be connected to the bus, so the input side of the AD520 needs to be powered from the main track, bus or some manner. Electrically it is the same. Main power in, the loop must be fed ONLY by the output side of the AD520.
–Randy
Hello All,
Thanks for the clarification, didn’t see the original post.
In the MRC AD520 instruction sheet, it notes that both the Red (feeder) wires to the unit are connected to the track between the turnout and the gapped (insulated) rails on the straight section. The Yellow (polarity shift) wires go to the reversing section on the opposite side of the gapped (insulated) rails.
It doesn’t matter which red or yellow wires go to which track polarity.
On the wye on my pike I originally put the feeder wires on the track between the two legs of the wye and attached the polarity shifting wires on the point end of the wye turnout.
The turnouts to the wye are #2 PECO insulfrog (unpowered) turnouts. When the points are thrown to the main power is not transmitted to the diverging line.
When the points are thrown to the diverging route both the main and diverging routes have power.
Both legs of the wye are gapped on all rails at the first joint past the diverging points of the turnouts.
This configuration didn’t work.
I moved the feeder wires to the AR unit “outside” the legs of the wye and VIOLA! Success!!
For the OPs situation, a baloon track, I would move the feeder wires to the point end of the turnout, keep the gaps (insulated rail joiners) on the tailing ends.
My point…
If the feeder wires to the AD520 are between the turnout and reversing section on the diverging side, and the turnout is a power routing- -no power to the diverging route when the points are thrown to the straight section, then no power will get to the AR unit when entering through the straight track.
When the points are thrown to the diverging track (where the AR unit is fed from) then the power will energize the AR unit and the polarity successfully reversed.
Unfortunately, I
Haha, I think that’s exactly what I was worried about, jj [:D]
I think gregc was looking at more or less the same issue, or similar…
it would be good to hear from the OP if the turnout to the reversing switch is power routed
Hello All,
Seems we’ve been “ghosted” again [:^)][%-)][:^)][%-)]!!!
Hope this helped
i wonder if the OP realized all his problems: trying 3 types of ARs and sending units back to the manufacturer – were simply caused by a power routing tunout positioned incorrectly.
yes this might be embarassing, but we all make mistakes. knowing if this is the cause would solve the mystery and be a great learning experience for all of us