Date   
Re: Reverse Loop Finder

Don Vollrath
 

Tom,
The problem occurs because locos in particular, as well as many passenger cars with lights will have electrical connections between the wheels and axles on the same side of the rails on the same or multiple trucks. This is done to aid power pick-up. When one of these multi-axle units spans across the gap where opposite voltage appears, it creates a short circuit.
DonV 

Re: Forgive my ignorance! Am I creating several reverse loops on my proposed layout?

Tom G.
 

Brian,

I’m missing your point. 

Thanks.
Tom

On Mar 4, 2019, at 6:45 AM, Brian Lewis <brian@...> wrote:

There is certainly a better way. It called 'Attachments'.......

I can scarcely believe that, in 2019, there are still elists  that do not allow them. Why is that pray?

On 04/03/2019 09:34, whmvd wrote:

--

Regards and thanks

 

Brian Lewis

Re: Forgive my ignorance! Am I creating several reverse loops on my proposed layout?

Don Vollrath
 

Tom,
Although there is a lot of loopy track that yields the appearance of bi-directional travel, I see only one actual polarity reversing problem section... Plus the turntable itself. It is the 'inside' loop of Red track running around the roundhouse near bottom left of the drawing. Easily solved with an auto-reverser with double isolating gaps at 1) the last turnout leading into the red loop around the roundhouse, and 2) each of the 2 Red staging tracks to the left of the roundhouse and the connecting Blue return line toward the top of the layout. Gap both rails at the frog end of those respective turnouts and wire that whole loop, including those 2 turnouts, through an auto-reverser. Be careful to ensure that you wire up all other double-track areas using the same Right-Left / North-South polarity convention so as to avoid polarity shorting issues at places where there are cross-overs despite which direction the trains will actually be moving. [With DCC forward is always forward.] If there is another path to actually cause a train to reverse directions on a previously traveled section, I don't see it..
However, I agree with Mark C. that the layout looks to be very tight with way too many short radius curves and steep grades.

DonV 

Re: Forgive my ignorance! Am I creating several reverse loops on my proposed layout?

whmvd
 

Don,

There's a lot of peering involved at detail really too small to properly see everything, but I'm quite convinced there's a reversing section on the richt-hand side as well. The small single-track piece between the two turnouts creates a nice short as it is.

I've only seen version 1 of the left hand side, and apart from the red part and the turntable, there was another reversing section involving most of the yard. Either that, or I fell into the too-little-detail trap, or in V2 it was changed.

Wouter

Wouter


On Tue, 5 Mar 2019 at 02:59, Don Vollrath <donevol43@...> wrote:
Tom,
Although there is a lot of loopy track that yields the appearance of bi-directional travel, I see only one actual polarity reversing problem section... Plus the turntable itself. It is the 'inside' loop of Red track running around the roundhouse near bottom left of the drawing. Easily solved with an auto-reverser with double isolating gaps at 1) the last turnout leading into the red loop around the roundhouse, and 2) each of the 2 Red staging tracks to the left of the roundhouse and the connecting Blue return line toward the top of the layout. Gap both rails at the frog end of those respective turnouts and wire that whole loop, including those 2 turnouts, through an auto-reverser. Be careful to ensure that you wire up all other double-track areas using the same Right-Left / North-South polarity convention so as to avoid polarity shorting issues at places where there are cross-overs despite which direction the trains will actually be moving. [With DCC forward is always forward.] If there is another path to actually cause a train to reverse directions on a previously traveled section, I don't see it..
However, I agree with Mark C. that the layout looks to be very tight with way too many short radius curves and steep grades.

DonV 

Re: New file uploaded to w4dccqa@groups.io

 

Trying not to put insulated gaps on curves. and try to minimize rail joints on curves. if you need to add rail joints on curves first connect them as two straight sections then make the curve.
Look at some YouTube videos on connecting track will help you understand the process.

Re: New file uploaded to w4dccqa@groups.io

Dale Gloer
 

If you don't use insulated joiners and cut gaps with a razor saw or whatever?? be sure to fill the gaps with some insulating material like styrene.  If you don't you can be guaranteed that sooner or later one of those uninsulated gaps will close and you will tear your hair trying to find what is wrong.  As the saying goes "Been there, done that, got the Tee shirt".

Dale Gloer

Re: New file uploaded to w4dccqa@groups.io

Don Vollrath
 

Your sketch is correct and the reversing section between the balloon loops will work as intended. Simply place insulated joiners at the frog end of the turnouts as you indicate. No need to cut any gaps as far as that is concerned. If you plan on dividing up the layout more for signaling blocks or CB controlled power districts using insulating joiners at turnouts is the easiest way. But if you do cut gaps... be sure to fill them with plastic or epoxy to ensure that they will never close due to rail expansion or other movement.
DonV

Re: Forgive my ignorance! Am I creating several reverse loops on my proposed layout?

Don Vollrath
 

Wouter, I'm assuming that there are no crossover attachments between tracks except where there is an indicated turnout. [Exception - there is a 30 degree X in the tracks near the turntable.] All other 'intersections' in the sketch are at different vertical levels with no actual connections between tracks. I don't see any path selections that actually reverse the direction of train travel except for that one loop around the roundhouse. Putting insulating joiners or gaps at the three tracks leading upwards from that loop isolates them from the actual reversing loop. Complete the isolation of the loop at the first turnout going towards upper right.

DonV

Re: Wiring problem

Charles Cauble
 

I think I have the diagram of the loop in an albumn now.  any suggestions of where to locate the MRC auto reverser?
I'd appreciate any help.  Thanks.

Re: Wiring problem

Tim Johnson
 

Charles, I'm glad you were able to find the photo section, and get your track diagram posted.

You've already got both rails of the loop section gapped on both ends of the loop. You need to attach the auto reverser so that the wires from the main section go on the non-loop side of the reverser, and the wires from the loop track go into the loop side of the auto reverser.

Now, you have a branch off the right side of the loop to consider. Is this a spur, or does it reconnect with your main track somewhere further down? If it's a spur, no problem. But, if it reconnects to your main track you may have another loop depending on how it reconnects.

The further consideration is that you want to be careful that you don't have wheels bridging the gaps on either end at the same time. This is usually stated as no train longer than the loop from gap to gap. The idea is that you don't want the possibility of metal wheels bridging the gaps on one end at the same time as another set of metal wheels are bridging the gaps on the other end. That could also happen with two trains, one entering and the other exiting at the same time.

Tim
Timothy A Johnson, Tucson, AZ (www.sbb-bls-bahnen.com)
European Train Enthusiasts, Central Arizona Chapter (www.ete.org)
On 3/5/2019 1:50 PM, Charles Cauble wrote:

I think I have the diagram of the loop in an albumn now.  any suggestions of where to locate the MRC auto reverser?
I'd appreciate any help.  Thanks.

Re: Wiring problem

Tim Johnson
 

Oh, one thing to check before wiring in the auto reverser. Make sure the loop is in fact electrically isolated from the main track; both rails. If it's not, that would be your shorting problem.

Tim
Timothy A Johnson, Tucson, AZ (www.sbb-bls-bahnen.com)
European Train Enthusiasts, Central Arizona Chapter (www.ete.org)

Re: Wiring problem

Jay
 

Hi Charles,
Yes, it looks like a loop. 
Where the  + & - marks are about where both rails should be isolated.
I agree with Mr Tim on the other points on this.

Jay
AT&SF

Re: Wiring problem

Charles Cauble
 

Ok. Thanks for the info. I’ll give it a try and see if my system will stay up.  I don’t have any connections on the spurs and they work fine so far but was afraid my isolations on the turn outs was causing the problems. I’ve added back drops to the ground or positive sides after them at any dead track. I’ll retry after everything is checked with being hooked to the correct bus.   Thank you
charles

Re: Wiring problem

Charles Cauble
 

Hi, It's me again.  After days of trying, no success yet.  I've added a more detailed photo (Loop wiring) to the gallery. I have tried so many location for the MRC that i finally started using alligator clips.  i have managed to get all my "juiced" turnouts to work and  my locomotive will run everywhere either direction except at point A. There it shorts out either direction.  The tracks inside the loop are not connected.  It turned out that I had some "dead" spots and I've corrected them.  My NCE system does not short out until crossing "A".  I thought about moving "A"  just before turnout "4" but have hesitated because in order to stop derailments I soldered flex tracks for a smooth curve and I would hate to do it and it not work.  I have 2 MRC units and so far no luck.  my next step would either use a frog juicer or an AR1.  I thought maybe the MRC is not sensitive enough to reverse and a AR1 is supposed to be adjustable? Any suggestions?
Charles

Re: Wiring problem

Carl
 

Hello Charles:

Perhaps check the MRC units on some loose track. Just two sections connected with insulated joints. Power straight to one section and power through the MRC unit to the other. Then use your alligator jumpers to "short" across the gap. Test lamps would be nice here.

If they work this way, then you face more checking on your layout. I use a "beeper" with clips to check for any cross connections between sections. With the wires loose on your reversing section there should be NO beep at all.

Good Hunting, Carl.

On 3/10/2019 2:12 PM, Charles Cauble wrote:
Hi, It's me again.  After days of trying, no success yet.  I've added a more detailed photo (Loop wiring) to the gallery. I have tried so many location for the MRC that i finally started using alligator clips.  i have managed to get all my "juiced" turnouts to work and  my locomotive will run everywhere either direction except at point A. There it shorts out either direction.  The tracks inside the loop are not connected.  It turned out that I had some "dead" spots and I've corrected them.  My NCE system does not short out until crossing "A".  I thought about moving "A"  just before turnout "4" but have hesitated because in order to stop derailments I soldered flex tracks for a smooth curve and I would hate to do it and it not work.  I have 2 MRC units and so far no luck.  my next step would either use a frog juicer or an AR1.  I thought maybe the MRC is not sensitive enough to reverse and a AR1 is supposed to be adjustable? Any suggestions?
Charles

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Re: Wiring problem

Don Vollrath
 

Charles, I only see the photo you posted on March 4 in your photo folder. Is there a different one?
It is possible that the MRC reverser is just too slow to work with the NCE 5 amp command station and booster (or possibly faulty).
You should be able to verify action of the Auto-Reverser by simply using an alligator clip jumper across any isolating same-rail gap. The A-R unit should simply flip to make the net voltage across the gap to be zero (the same polarity) and the booster should never trip out. Make sure the wire gauge from the booster to the reverser and then to the loop track feeders is at least as big as 18 AWG, and that there are track feeders reasonably close to the isolating gaps in the track. I recommend using an OG-AR. But a dual frog joicer when installed properly should also work.

DonV 
 

Re: Wiring problem

Don Vollrath
 

Aaah. I found your other photo. [I expected it to be in the same 'album' as the first]
I suspect that the feed wires to the input of the A-R unit are a weak electrical service connection. Wiring to the input side of the A-R unit should be directly connected to the booster, NOT the constant polarity track leading up to the reversing loop. The difference???  A matter of the total electrical resistance in the current path, and therefore short circuit current available for the A-R unit to quickly sense a polarity mis-match and make a correction before the booster trips out. Using alligator clips with typical small gauge wire for testing doesn't help.

The A-R unit will naturally/always start up with the output phasing in the same direction. [Satisfying point B as you describe it.] Once the poor electrical connections to the A-R unit or to the track cause a delay in tripping a polarity mis-match at point A, causing the booster to trip, It will never recover as when the booster trips, operating power to the A-R unit is lost, causing it to restart when the booster recovers in the normal startup position... with matched polarity again at point B and the mis-match again at point A. Flip the polarity to the input of A-R unit to test my theory to see if now the issues occurs at point B.

Making your wiring more robust should certainly help... including good wire feeders near both sides of the isolating gaps on each rail.
DonV

Re: Wiring problem

Charles Cauble
 

Don,    would connecting  the input for the MRC to the bus wires (14 gauge) be connecting to the booster, correct? (NCE unit)

charles

Re: Wiring problem

Craig Zeni
 

My experience with the MRC breakers was that they were too slow; the NCE boosters always kicked out first.

Craig Zeni
Cary, NC
Despatched from my infernal Android

On Sun, Mar 10, 2019, 18:33 Charles Cauble <drbeetlebaum@...> wrote:
Don,    would connecting  the input for the MRC to the bus wires (14 gauge) be connecting to the booster, correct? (NCE unit)

charles

Re: Wiring problem

Charles Cauble
 

Well I soldered the yellow wires inside the loop right next to the double isolated rails (where + meets -) and connected the red wires to the bus lines. Only 6 inch wires either side of the MRC.  Unfortunately there is no change with good connections.  The system stays on and the loco shorts it at the A gap.  I went under and switched the red wires to opposite bus lines and now the whole system shorts.  I’m running out of ideas.  Any more would be appreciated.
charles