How does a Wye work?

Discussion in 'FAQs' started by spitfire, Jan 10, 2003.

  1. spitfire

    spitfire Active Member

    Is it for turning trains around so they can go back the way they came? How much room does one need in HO? If that's not what it's for, is there any other way (besides the giant hand-operated crane or a reverse loop) to turn them around?
    (I'm really biting my tongue here and holding back from saying this is in any way a "dumb" question :D )

    :confused: Val
  2. Railery

    Railery Member

    One type of wye is the "Stub wye" which is the simplest wye for reversing purposes only. It is also the smallest size for a wye.

    There are a couple more wyes; Wye for diverging routes and a scissors wye. U can also do a double track wye.

    Here is a pix of a stub wye.
  3. Vic

    Vic Active Member

    Hi Val, Yep you hit the nail on the head for the purpose of the Wye.:)

    In some instances a Wye was just used to turn a loco and a caboose back in the opposite direction and in other instances Wye's were large enough to turn entire trains around. There is a Wye here that is large enough to turn around a 15 car passenger train. Of course it hasn't been used in years but its still there and occasionally they do turn some MOW equiptment on it. One leg of it is part of a branch line to a small town south of here.

    Railey's pic shows a wye made from sectional track components but using flex track a wye can be built as large as needed. Just remember that each leg has to be longer than the longest train you will be turning on it. I've indicated those points as "A" on Railey's diagram. Also there's nothing wrong with a few sidings coming off the wye if you want to. Also part of the wye can be incorporated with other trackage...for example a leg of the wye can be part of the mainline for another route.

    Attached Files:

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  4. billk

    billk Active Member

    Shouldn't the tracks that has to be longer than the train be the tracks that extend from the point end of the switches? I.e. The red parts of the (very rough) diagram attached?
  5. spitfire

    spitfire Active Member


    Thanks Railery and Vic! This will be very useful.

    :D Val
  6. jon-monon

    jon-monon Active Member

  7. shamus

    shamus Registered Member

    Once you have made it, time to wire it.



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  8. Hunkiedoo

    Hunkiedoo Member


    Linn H. Wescott's book "How to Wire Your Model Railroad", pg 26 talks about wyes & how to wire them.
  9. Vic

    Vic Active Member

    Bill K. be's 'zactly right!!!:) I made the assumption:eek: that the leg that is not marked "A" was simply a lead track to the wye and would by its nature be long enough.
  10. davidstrains

    davidstrains Active Member

    you also have to consider the "reverse loop" characteristics when wiring it also.
  11. aartwmich

    aartwmich Member

    Hmmm...should we check Val's trackplan post to see if she's incorporated a wye in it??
  12. spitfire

    spitfire Active Member

    You guessed it girl! I am indeed considering the most excellent wye for the town end of the layout.

    Shamus, much thanks for the wiring diag.

    :p Val
  13. 60103

    60103 Pooh Bah

    There are other forms of wye besides the euilateral one shown. You can have one straight track with 2 quarter circles coming off it. In this case, the size of the wye is R x 2R (R is your radius) plus a bit for the switches plus the tail track. There's another wye in one of the plans that's being discussed in track planning this month.
    Your wye will need a separate direction switch (like a reverse loop) as well as a reverse switch for the main line which is not the same as the reverse switch on your power pack.
    Unless it's part of your trolley line?
  14. spitfire

    spitfire Active Member

    Shamus, I'm taking a closer look at that diagram and I have a question. On the 3 turnouts you've shown are the frogs powered or insulated? Or are wye turnouts always a certain way?

    David, it's not for the trolley line, which is going to be a round and round loop - just like the prototype I might add!!! Since I'm setting up a point to point trackplan, I thought it would be useful to be able to turn at least the loco around for a return trip that would ultimately end in my staging area. Maybe the staging could be modelled as a yard of some kind.

    And maybe I should continue this thought in the trackplanning section.....

    :p Val
  15. cidchase

    cidchase Active Member

    Hi Val,
    If powered, the frog should be connected through a single relay or switch contact to the same point rail (movable) which is in contact with the stock (outside) rail in either switch position.

    Only one of the point rails contacts a stock rail in either position of the switch.

    I believe this is always true, wye or not, DC or DCC, unless it's a stub switch, but that's another story!!
    :D :D
  16. Railery

    Railery Member

    Hi Val. Most turnouts are powered (Atlas). U still will need to reverse the power in the end section to come back out. This diagram shows X being power and Y being ground. You only need one gap in the mainline as is shown. The double pole double throw switch reverses the track polarity to match the mainline going in or coming out.
  17. shamus

    shamus Registered Member

    Using Peco points, that arrangement will cause a short as you cannot feed power back into a turnout which have live (Electro) frogs. Therefore please, insulate both rails. If you are not using Peco track, then possibly the above will work . Never used or even seen Atlas track


  18. spitfire

    spitfire Active Member

    Hmmmm. I was looking at Peco turnouts today (code 83) at the LHS, but was put off by the fact that they had electro-frogs. Although I am still just at the planning stage, I thought the wiring required seemed more complicated. Now, looking at these diagrams I'm not so sure.

    Also, I think the wiring for DCC might be a lot simpler, but again, I'm not sure. The easier the wiring the better, since I have no experience with it.

    Anyone have any thoughts on this?

    :confused: Val
  19. Gary Pfeil

    Gary Pfeil Active Member

    I think the simplest approach is to use DCC (you mentioned it afterall) and Atlas turnouts. You would need insulated joiners on all three of the "inner" rails of the wye. That is, between frogs. One leg of the wye, usually a stub ended one but selection would depend on situation, is chosen for the reverse block. It is gapped on BOTH rails. It's two rails are connected to a reverse module, which in turn is connected to the DCC track buss. Feeds to the track buss from the point side of all the turnouts will power all the routes. I think the Atlas are good turnouts, particularly for beginners. Peco Insulfrogs would work the same. Come to think of it, Electro frogs wouldn't require any special attention here. Keep in mind the only "problem" with Electro frog (Peco as well as Shinohara, etc.) is that track power should never come into the turnout from the frog end. So gaps on all frog rails are required, and extra feeds are required for resultand dead spots. The gaps are needed in this case anyway. The big differance with DCC is NO SWITCH WIRING, or throwing. Here is a quick and dirty sketch of the gap and feed requirements.

    Attached Files:

  20. spitfire

    spitfire Active Member


    Gary - thank you! I think the light of comprehension is dawning in my brain. One more question, though. It sounds from your description that I have to totally isolate the electro frogs for DCC, which sort of defeats the purpose and adds a lot of hassle, don't you think?
    I was looking at some Pecos this afternoon and I almost bought a few, but then I thought I'd better check it out here first.
    Oh and one more question, why do you reccommend Atlas turnouts for beginners? I liked the Peco's much better - they seemed a vastly superior product. Are they harder to work with? Fussier to install? They had such a tight click... I was pretty sold.
    Thanks for all your help Gary!

    ;) Val

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