WYE problem - DCC HELP !!

[hepkat63]

Hi All,

sorry.. but I am at the end of my rope with this !   I have a Y section (wye) in my layout, that no matter how I wire it - I can't get it to work properly.

My layout is all DCC - digitrax and kato unitrack.  I have a short two sectional track y section at the end of my layout that goes around the corner (s) which is integral to my layout and I can't change it now !

I realised I need an AR1 - which I have several of.  I have wired these up before (on other parts of my layout) and they work fine - but this one - although I think I have it working - it 'shorts' out when a train goes over it - a LONG train.  This, I think is the issue.  When  loco goes over it - it seems to work fine, but when one of my long passenger trains goes over it - the short occurs.  I have researched the digitrax website and they advise to 'watch out' for this - but how do I get around it ?  Can anyone help?  I have changed the configuration, and isolating jumpers so many times, I can't think anymore !  I have attached a picture of my diagram.  Do I need one or two or three AR1?  Where do I terminate/isolate?  How do I get around the long train problem?  Any help GRATEFULLY accepted !

 

[selector]

I don't quite understand your situation, but if you have metal tires going over gaps at the same time, you'll get a short.  So, it might be good to stagger the gaps at each end by maybe 5/16".  To see if this will solve your problem, try a piece of packaging tape about 1/4" from the end of one rail and covering the very end as well.  If it works, you know what to do: either paint that end with clear nail polish or poly-urethane, or redo the gaps with that stagger.

The wisdom is to not have any part of your train outside the two gaps in a reversing section.  Leads to all sorts of frustrating experiences and puzzles.

Crandell

[rrinker]

Exactly how are those 3 legs connected to the rest of the layout? If sya the left and botom sides are part of the continuous layout going around the curve, and the leg to the right is just a dead end for reversing locos, what you cn do is insulte both routes of the right-hand turnout - after the frog, and make the turnout plus the dead end section the reversing part controlled by the AR1. What is happening is that by making just the one curve side the reversing section, you have metal wheels crossing the gaps on both ends at the same time when the long trains are running. The reversing part of the wye does NOT have to be one of the three internal legs, it can be any of the tails instead, and this should allow you to get a section as long as or longer than the longest train expected to run there.

                     --Randy

 

[Texas Zepher]

It all depends upon which legs the "long" train can come and go down.   Can the train come from any of the three and exit to the other two?

When you say two track sections do you mean sections like Atlas track 9" straights? 

I am guessing that one of the legs will have to be extended down the track as long as the longetst passenger train.  That is the track with the reversing unit hooked to it would be a true "Y" shape.  The tail of the wye will be as long as the passenger train.  The track connecting the top of the two ends of the "Y" should be in the normal wiring and should be the most commonly used route through the "wye".

 

[hepkat63]

Hi Guys,

thanks for the suggestions - sorry I wasn't quite clear enough.  Yes, although the picture I submitted depicts my situation - it is part of a large track.  The left hand side goes off down a large straight into a shunting yard - usually where the large passenger trains come from.  So, the can go straight on - and keep going around the back of the track along a long back straight, or turn right and come into the main viewing area.  coming the other way, they come from the main viewing area and either continue around to the right onto the back main straight, or go left to the shunting/switching area.   On the digitrax site, they have one diagram that says not to look at it as two reversing loops, but just one ?

[hepkat63]

Hi Randy,

thank you for the reply - please see my other response - the wye is part of the complete track - all is live.

[hepkat63]

Hi Crandell,

thank you for your reply.  I am using kato unitrack, so I just swap out the regular track joiners for the kato isolated joiners.  I can't really stagger them I don't think?

[rrinker]

 OK, so the right-hand side goes down a long straight - is it long enough so that you can insulate it from the rigth hand turnout down to a distance equal to your longest train? If so, do that, and power that section with the AR1 output. Insulated joiners would be needed on the two legs to the left of teh frog on the right-hand turnout and then at some point along the logn straight.

                  --Randy

[Motley]

Yes listen to these guys, they are right. I had the same exact problem on my wye with lighted passenger trains. I just extended the reversing section on the leg of the wye, by placing the gaps about 8' down the track.

Please post your track plan so they they can tell you where to place your gaps.

[hepkat63]

Here we go - more photos.  I have insulated the left turn and the top straight of the wye .  The AR1 is powered directly from the PSU and the Reverse loop is powered to the left of the left hand side turnout.  Seems to be working now?

[hepkat63]

I have put the insulators on the left hand part of the wye and the top straight part of the wye with the AR1 powering the left hand side of the track before the turnout - seems to be working now?

[selector]

Your gaps are in the wrong place as far as I am able to understand your setup.  For the huge majority of us who have such a set-up, you pick one side of the triangle and gap it as close to each turnout at either end as you can.  That gives you the full length of a side to switch polarities once your full train is between the gaps.  Or, as Randy suggests, just gap the long tail on one corner.  You don't appear to have such a tail, but you have something like it going out the bottom right of the last photo.  So, you would insulate right at that last turnout, and then some distance outside the photo's right side....just enough to give you a reversible length of track.  Reversible electrically, too, of course, either with a DPDT or an auto reverser.

Crandell

[richhotrain]

Placing the gaps where you indicated, you have not completely isolated a reversing section of track from the main bus.

Since your passenger trains look pretty long, and presumably have lighted passenger cars. you are going to need a reversing section long enough to accomodate the longest train.

The first step is to move the gaps on the lower left all the way down to the left leg of the wye.   Then, add a third set of gaps to the left of the right hand turnout leading toward the wye.  That will isolate a reversing section of track from the main bus and, hopefully, be long enough to accomodate your longest passenger train.  If not, then you need to gap the tracks elsewhere in order to create a reversing section of track long enough to accomodate your longest passenger train.

Rich

[Hamltnblue]

How about a couple of more pics.

You showed the Y but not the section to the right of it.  Does it continue around and re-connect or does it end somewhere to the right?

[hepkat63]

thanks guys for all the replies - I am overwhelmed by the fantastic responses!  Ok, I am pretty sure it is all working now. 

The isolated track seems to be ok by following Rich's and other advice as above.   Again - thank you very much.

[richhotrain]

hepkat63

thanks guys for all the replies - I am overwhelmed by the fantastic responses!  Ok, I am pretty sure it is all working now. 

The isolated track seems to be ok by following Rich's and other advice as above.   Again - thank you very much.

Nice job, hepkat63.  Congrats on getting that reverse sectiion up and running.

Rich

[Texas Zepher]

hepkat63

I have put the insulators on the left hand part of the wye and the top straight part of the wye with the AR1 powering the left hand side of the track before the turnout - seems to be working now?

Yes, the insulated joiner place in the picture looks good to me.   So the whole yard area shown in the second picture is now on the reversing loop circuit.   The reverser will trip to the correct setting depending on which leg of they wye the train leaves on.

[cv_acr]

Texas Zepher

hepkat63:

I have put the insulators on the left hand part of the wye and the top straight part of the wye with the AR1 powering the left hand side of the track before the turnout - seems to be working now?

Yes, the insulated joiner place in the picture looks good to me.   So the whole yard area shown in the second picture is now on the reversing loop circuit.   The reverser will trip to the correct setting depending on which leg of they wye the train leaves on.

If that's a stub-ended yard, and that whole leg of the wye is the reversing section, it should work just fine.

The only thing I'm not sure of is how much current the reverser can handle, if you have several passenger trains in the terminal at the same time with multiple locos and lighted cars. Should be fine though.

The key thing, and what was causing your original shorts is that the reversing section needs to be longer than your biggest train. Some people will say just the engines, but if you have metal wheels on all your cars, and especially in your case because you are running passenger trains with lighted cars, you will bridge the gaps at both ends of the reversing circuit and cause a dead short if the isolated section is not long enough.

If you only have a small piece of track between the terminal and the wye switch isolated, you'll still have a problem when you run a passenger train in or out of the terminal and it bridges the gaps at each end of the isolated section.