Using a Wye for a Reverse Loop

Do you mean something like this?

If so, sure, you can do it.  You just have to do some wiring to the loop part to flip the polarity of the rails so you don't get a short, and if you're in DCC you can get an autoreverser that will do it for you.

Hi Phillip,

 I started to lay a conventioal loop at one end of the layout, but wanted to be able to reverse direction both ways which would mean another reverse loop. This is going to eat up a lot of real estate so I thought by using the Wye it would eliminate an extra loop.

Also shouild I have posted this in the wiring section?

Bob

Phillip,

You figured it out exactly.

Thanks for you help.

Bob

Yeah, it's definately doable.  You just need something to flip the polarity of the rails for you.  You see, as the tracks go around the loop they turn back on themselves, but now the inside rail becomes the outside rail, and vice versa.  Since the polarities are different you'll have a short circuit there if you don't change the polarity if the exit rails from the loop area.  There are lots of ways to do this.

Are you using DC, or DCC?

The tail of the wye will determine the maximum train length unless you first take apart and then reassemble the train.

Mark

Yes, I'm using DCC and have a reverser from Tony's Train Exchange but haven't hooked it up. I alternate working on the wiring underneath the layout with working on top laying track.

The next step will be to redo the track and install the Wye.

 Patience is truly a virtue. 

Bob

Hey Mark,

Check my drawing. After going through the wye the train will switch to the inner main line. Will this should solve the length problem.

Bob

I solved the real estate problem by stacking the loops. You get two loops in little more than the space required for one. Each loop of course has it's own lead tracks on opposite sides of the loops, but the balloon tracks themselves take up no more real estate than a single loop. To do this of course, your mainline would have to rise from one loop to the other a minimum of 4 inches (assuming HO).

On my previous layout, I used a little bit different approach. My balloon staging yard was in an adjacent room and both ends of the mainline fed into the same loop, with a double slip turnout at the throat. A double crossover would work as well but would require a little more length. With this arrangement, trains could enter the loop from either end of the main. All trains would travel around the loop in a counter clockwise direction and could re-enter either end of the mainline depending on how the double slip was set.

For me, wyes are a good solution for turning the locomotive, but I see problems using them to turn the whole train. For one you would need two tail tracks that can accomodate an entire train length and that can eat up an enormous amount of real estate as well. Second, you would have to back the train up through one leg of the wye and depending on train length could cause problems with derailing. I would give this some thought before settling on a wye.  

Thanks for the idea but I don't have the space for a 4" rise. I'm afraid I have a Champaigne appetite bur a beer budget. I may be trying to do too much in too small a space.

Bob

I think the wye will require more real estate than a reversing crossover from main to main.  The "dotted" lines in the diagram above will have a reverse curve sufficient for the tail track to be parallel with your straight mains.  You will need two of them, making the distance from main to main twice what you'd need for a reversing crossover.

Hi Cordon,

You're right. Last night I placed the track as planned on top of the layout and I ended up with just one true reverse loop. Getting to the stem from both directions just isn't practical particulary with my space limitations.

As you can probably tell I'm adlibing my track plan but in trying this I did end up with improvements to the over all layout.  I'm going back to regular reversing loops. This is the fun part in building the layout for me.

Thanks,

Bob

 Yes your post covers what I had in mind. Thanks for your comments. They add to and comfirm other advice. I had not realized the complexity of what I am trying to do both in theory and in actually laying the track to fit the situation. Maybe way too much for a newbe.

I've got to walk away from this for a while.

Thanks again,

Bob

pcarrell

Yeah, it's definately doable.  You just need something to flip the polarity of the rails for you.  You see, as the tracks go around the loop they turn back on themselves, but now the inside rail becomes the outside rail, and vice versa.  Since the polarities are different you'll have a short circuit there if you don't change the polarity if the exit rails from the loop area.  There are lots of ways to do this.

Are you using DC, or DCC?

 

i came upon a short circuit, then i seen the rails when back on themselves. i quickly disconnected and started my research

im also using DC only

i have some isolating connectors on order, they might take awhile, i live 400 miles from the store i had to order from.

do i isolate the wye connector from the rest of the rail?

how is the proper way to wire the loop?

thanks

jack

A wye means a tad more hands-on operation than the reverse loop -- especially with a DCC auto-reverser.  This may have a bearing on your Givens & Druthers assuming either choice is doable.  So, which style suits your operations-preference?

tgindy

A wye means a tad more hands-on operation than the reverse loop -- especially with a DCC auto-reverser. 

Why so?  It's a turnout with two curved segments rather that a straight segment and a curved segment?

hi Jack,

For proper wiring buy a book. It's very easy to explain with a good picture; a good picture tells more then a million words.

http://www.kalmbachstore.com/12412.html

Hi Bob,

the biggest problem with a wye is to find a place for it with a long enough tailtrack. When you have a double track oval the two entrances to the wye will become busy places. If you even need (not want) to install signals depends on the number of trains that will be running at the same time. With two operators it will be doable to keep an eye on the other; with more operators at the same time the result will be a predictable head-on.

Paul

superbe

I've got to walk away from this for a while.

Hi All,

Since my 2008 thread has been reopened, I thought I'd report the happy ending to my inquiries. Using wyes in my case took up too much space so I created a track pattern inside the circular main in the form of an X using turnouts and a 90 degree cross over. That gave me the two reverse loops.

With lots of good help from the forum I wired it using two PSX-AR reversing modules from Tony's Train Exchange. I'm using DCC.

They work like a charm.

Bob

Hi Bob,

 I didn't noticed your thread from March 2008 was hijacked by Jack.

Paul

Doc in CT

[Why so?  It's a turnout with two curved segments rather that a straight segment and a curved segment?

While either method turns trains -- there are more turnouts in a wye.

 Oh

So we are talking about a Y  as opposed to a Wye turnout.  Bit more annoying for proper DCC operation.

I think this is what it should look like (I planning on moving the gaps away from the turnout to give the rails time to move).

Jack, your wye turnout is wired and joined normally to the oncoming main line that then goes on to form the loop via the turnout.  It is at the two split routes of the turnout that you place gaps.  Use insulating plastic joiners if you wish.  Some guys, like myself, don't like how they look, so we leave a gap and fill it with some styrene left over from a model kit.  Glue it in place and file it to look a lot like it belongs.  That means four such gaps.

So, you now have a layout complete, including power feeders up to the two routes on that wye turnout.  You have the loop rails in place and gapped right at the place where each end meets the wye turnout.

Now you must wire those dead rails, and you do it the same way as the rest of the layout EXCEPT that there must be a double-pole double-throw (DPDT) toggle switch wired in series somewhere cut into that pair of feeders.  There are diagrams on the net showing how to wire a DPDT to reverse polarity.  But you must feed that loop.  It's just that you need to be able to flip that toggle once the train enters the loop and the last metal axle clears the gap.  From there, you know you can safely cross the gap at the far end.

-Crandell