Turnout Position

Discussion in 'FAQs' started by Pitchwife, Nov 14, 2002.

  1. Pitchwife

    Pitchwife Dreamer

    This is probably an odd question but here goes. Refering to the attached diagram, the points are thrown in the direction of the red arrow so that a train traveliing from direction A will continue through to B. Without switching them, will a train traveling from direction C go through to A without a problem or would there be a significant chance of derailment? I've noticed that when I laid out a short test section it worked, but am unsure if it would work in a real life situation. I'm in the process of determining my wiring and laying out my control panel and one less switch to worry about would help. There isn't a situation where a train would need to go from A to C so that's not a factor. Also, this is in an unseen section of the layout so the visual detail is unimportant. Has anyone ever tried this before?

    Attached Files:

  2. billk

    billk Active Member

    Each wheel going through the switch has to spread the points apart enough to let its flange through. Whether it can or not depends on the weight on the wheel, how much up/down play it has, the width of the flange, what's holding the points in position and with how much pressure, etc, etc.

    So even though it works on your test track (good idea, btw) you'd have to hold your breath everytime you got a new piece of rolling stock. Sounds like a recipe for disaster, especially if your "unseen section" is also hard to access. Is this part of a reverse loop?
  3. Clerk

    Clerk Active Member

    Hi there Pitchwife.
    My first layout was HO. While running trains I accidently ran thru a switch, on you diagram from right to left. I didn't realize it until later after several trips through it. Then I tried other switches and it worked very well. After that I started building N scale and the first time I ran through a switch, the engine when through and a couple of cars , then the derailments started.

    I may be wrong, if I am somebody else can correct me but I think the reason the HO went through the switch is that the cars are much heavier and I don't believe that the spring in the switches are any stronger than N scale. Therefor the N scale cars are to light to go through the switch . I have no trouble runing engines through or heavy cars as they will trip the point.. I don't believe that the N scale should be run throug as it can weaken the return. points.
  4. Pitchwife

    Pitchwife Dreamer

    Hi guys
    Thanks for the input. I guess that it is a cousin of the reverse loop. The switch would be used to shunt cars from two tracks, each running in a dedicated direction to a shared track. The only thing that would hold the points in position if this works is the natural position of the switch. The real drawback is as billk said, that it is in a fairly inaccessable area. I forgot to mention that this is an HO setup so it sounds like I might be able to get away with it as long as I made sure that all of the rolling stock carried enough weight. The only other alternative I came up with was a sensor that would automatically throw the switch. It would add a little to the complexity of the circuitry but not as much brainpower as it would take me to remember to do it myself. :D
  5. billk

    billk Active Member

    Additional thought (probably reached my daily limit) - Spring-load the points, ala Peco, with as little pressure as you can get away with.
  6. Vic

    Vic Active Member

    Trolley lines used that arrangement to go from one line to another but like Bill said it may be a "recipe for disaster" in a switching situation. I think the weight of the cars is just going to be too critical. Perhaps just adding a set of indicator lights to your control panel to remind you which way the turnout is thrown would be a simple solution....Have reached my "daily limit" of thought too!!!:D
  7. Gary Pfeil

    Gary Pfeil Active Member

    What brand turnout is it and does it have a switch machine on it? I'm thinking Atlas without a machine, it will certainly let traffic thru without derailing anything, but it will not realign to the other route afterwards. In order for all equipment to get thru with a machine the equipment would need to be fairly heavy. BTW, this arraingement would be called a spring switch. Common in G scale, don't know of any in HO.

  8. shamus

    shamus Registered Member

    Hi Pitchwife,
    That arrangement of tracks is fine if you are using trackwork like PECO for instance as they latch each way. If you are using some other brand which doesn't latch, then you will need to be able to latch them in position using ground throws or point potors that do latch like Seep motors (New version)
  9. 60103

    60103 Pooh Bah

    I have to disagree with Shamus on this. I think that Snap Switches will let some rolling stock trail through because the spring is light. On Peco the spring is heavy and it would take a really heavy unit to shift the points. If it works with your rolling stock, good. But I would expect problems sometime in the future.
    The other consideration is: do you want the switch to change to C or to stay routed to B?
  10. Pitchwife

    Pitchwife Dreamer

    The switches that I am contemplating using are the Atlas Mk3 Customline #6 switches. Any tension needed to hold the manual switch in position could be supplied by a very light rubber band. That should hold the points in position while at the same time allowing them sufficient give to let the wheel flanges pass through.
    One unusual feature of my proposed layout is that there are two mainline tracks, each dedicated to a single direction with several common tracks just to keep things interesting. This switching situation is access to and from either end of the common stageing area where trains can be assembled and routed in each direction. C to A is from one mainline to staging and A to B is from stageing to the other mainline. The directional traffic would be completely limited from A to B and from C to A. The beauty of the setup is that if I get bored with it the directiions can be reversed with only minor changes. :cool:
    I have been designing this on paper for more than two years and I think that I have most of the bugs worked out. Now it is minor things like this switching situation that I need to resolve. I'm glad to have this forum so that I can pick the brains of all of you more experienced modelers. I appreciate all of the input.
  11. shamus

    shamus Registered Member

    I must have missed the point of this, are you trying to let the weight of you rolling stock/loco move the turnout for you? if so, then PECO WILL NOT WORK.
  12. Pitchwife

    Pitchwife Dreamer

    Thats right Shamus. The points would be gently held in position allowing the wheel flanges to push through. At least theoreticly that is the idea. One of the other advantages to this, if it works, is the reduced cost of switch machines since there will be a number of other areas where this type of system would be used. That is one of the reason that I'd like as much input on this subject as possable. Thanks for yours.
  13. msh

    msh Member

    I apologize if I've missed something, but I always thought the points needed to be set to safely control the train's route and were not moved by the train itself - wouldn't that be a formula for derailments?? Do real trains do this? I sure didn't think so, seeing as the ground throws I've gotten close enough to see required three steps to operate and were always locked. Like I said, maybe I'm missing something. :confused:
  14. Pitchwife

    Pitchwife Dreamer

    Hi msh
    You're right about real trains, but as I stated earlier, this is going to be in an unseen area so visual correctness isn't a factor in this situation. I'm just hoping to simplify my operation.
  15. t. alexander

    t. alexander Member

    Yes, real trains do use spring switches. One place Ive seen them used is in a wye situation. There is no problem with the big boys as there's plenty of weight there.

  16. Vic

    Vic Active Member

    Park railroads and large scale live steamers use them too but again its massive weight that makes them work.
  17. Vic

    Vic Active Member

  18. Pitchwife

    Pitchwife Dreamer

    Sounds like I need to work on a proportional "weight to spring strength ratio". This may work after all.
  19. 60103

    60103 Pooh Bah

    The only full size spring switch I remember was on the Niagara St Catharines & Toroto (an interurban line) at the ends of a passing siding.
    I think the switch stands had a big S on them. They used a regular switch stand, but the throw rod had a heavy spring in it. I think it could be thrown th other way for reverse movements, but I don't know if it would spring in the reverse direction.
  20. wendell

    wendell Member

    Yes real railroads use this its called slip or spring switch Hobo railroad has one in newhampshire (usa). They also use them on car dumpers where the car is pushed up ramp to dumper dumped then push to adown ramp that is steep enougth to go throught aspring switch and up grade alittle then coast back thought the switch(really a switch back )to a storage yard. Wendell

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