DCC and switch machines

Discussion in 'DCC & Electronics' started by nwdstek, Dec 24, 2004.

  1. nwdstek

    nwdstek New Member

    I believe it is time for a re-think about switch machines. Here is my reasoning, see if you agree. For many years we have all used either manual, or electric switch machines which all have one thing in common. They force the point rails against the stock rails with considerable pressure and lock them there. One of the main reasons for this is that when running analog DC operating systems, a good electrical contact between the point and stock rail was important to smooth, reliable operation. It has been my experience that with DCC this is no longer the case. In fact, power routing switch points can cause problems. This means that the only pressure required between the point and stock rail is whatever it takes to keep your rolling stock from "picking" the points. I have been experimenting with this aspect for the last few years. I installed spring switches on a friends layout as well as my own. He has weekly operating sessions and the spring switches have worked great for over a year. We use them on the reversing loops at the ends of his mainline (mine too) The spring pressure required to hold the point rail against the stock rail is light enough that the train wheels easily push them out of the way when exiting the loop. This has proven, to my satisfaction, that DCC allows reliable operation while using very light pressure to the point rails. I feel this is going to open up many possibilities for smaller, simpler, cheaper, easier to install switch machines. Feedback?
  2. Fred_M

    Fred_M Guest

    So why do you think that DCC requires a lesser degree of electrical contact than DC? If anything DCC requires better and more reliable connections and lower resistance in the circuits and connections than a DC systems did. Fred
  3. nwdstek

    nwdstek New Member

    DCC/ switch machines

    I responded to Fred by e-mail and forgot to post a reply on the forum. I agree in most cases that a good electrical connection is important. The point I was trying to make is that power routing switch points are not required with DCC operation. Therefore a good electrical connection is not required at the points. This allows much more latitude concerning linkage and machinery to move the point rails.
  4. CalFlash

    CalFlash Member

    I also believe most DCC users either use turnouts with reliable electrical connections or add jumpers so that no mechanical contact is required for electrical purposes. That being said, I wonder how nwdstek wired the spring switch's frog. I'm using NCE SwitchIts to control the Tortoise machines for my reverse/staging loops and the auto reverser can automatically throw one of them as there is enough lead. The other one does not have enough lead to give the Tortoise time to throw the turnout before an engine runs into the frog rails.
  5. nwdstek

    nwdstek New Member

    frog wiring

    I use insulated frogs exclusively. There is no wiring to the frog. Inside the loop, the track is wired to the automatic reversing unit ( Tony's) and outside the loop the track is wired to the main power buss circuit. That's the beauty and simplicity of it. Also, by using a very light spring instead of a tortoise switch machine to hold the closure rails against the stock rail an approaching train will simply push the rails out of the way and continue. I believe that DCC allows more realistic simulation of prototype railroading where track switches are used only to guide the wheels of the train and not as part of the power circuitry.
  6. kchronister

    kchronister Member

    Forgive me for being contrarian, folks, but I'm just not understanding the imperative... Other than some manufacturers who make distinctly DCC-unfriendly switches, I'm unaware of any problems with "snap" or "tortoise" switches... I guess I'm just from the "if it ain't broke, don't fix it" school, but I'm not seeing the reason for this one... But if you can enlighten me, I'm up to learn...
  7. Gary Pfeil

    Gary Pfeil Active Member

    Interesting topic. I hope I can make my thoughts clear, have had a few already! I don't think its DCC which has made power routing turnouts less important, I think its the fact that all locos produced in the last, I don't know, 10 years?, have much better electrical pickup. Back in the day it was common for locos to stall on insulated frog tunouts. Probably doesn't happen much now. I say probably because my turnouts are mostly power routing, I handlay and wouldn't consider a "dead" frog. However, I do gap them at clearance points anyway, and could gap them as short as the insulated frogs on commercial turnouts. One thing for sure, DCC doesn't have any need for power routed turnouts to control the presence of power on a stub siding. With DC, i always used the postion of the turnout to control power for stub ended sidings, why add yet another block switch to a panel? Certainly not needed with DCC. But where I disagree most with the first post is that no one should ever have depended on the electrical connection between point rails and stock rails for operation. If you didn't wire the frog to change polarity with the position of the points, you were almost guarenteed to have stall problems eventually.

    I do think machines, or linkages, putting less stress on the points, is a great thought. Never really needed for electrical contact, they simply put too much stress on the throwbar.

    In one of my staging yards, I use Atlas turnouts. Because I only operate in one direction into and out of this staging, I have no machines or other linkage for these turnouts. I simply run trains thru and they move the points. I did however have problems with electrical conductivity, so I soldered feeders where required, and now all works well.

  8. nwdstek

    nwdstek New Member

    Thanks, Gary! Your response indicates you see the direction I'm going with this idea. I also have some areas on my layout where I use atlas switches in the same way. The light, easy action of the switch points is the main theme of my thread, not so much the power routing feature. I am trying to develop ways of operating switch points that don't require mechanisims that are half the size of a locomotive and cost as much as $16-$18 per switch. Yes, there are hand throws but they become less effective as the distance from the edge of the benchwork increases, and do not work very well with hidden track. They also lock the points against the stock rail which promotes derailments if a train is accidentally run through a switch "the wrong way" As I intend to operate my switches from my throttles using stationary decoders, my focus is on electrically powered switch machines.

    I have built a prototype of a very compact, very inexpensive, easy to install, low voltage stall motor type switch machine which I plan to install on the switches on my layout. It works very well on a test bench but it needs to be used in actual operation for a period of time to determine reliability and longevity. Minimal effort in moving the closure rails is key to the development of this device. I was curious to see what the response to this idea would be especially concerning any possible drawbacks that I might have overlooked. I thank all who have responded and look forward to further discussion on this topic.
  9. Gary Pfeil

    Gary Pfeil Active Member

    I'd certainly like to see what you've got. So far I've handlaid turnouts without hinging the points, so it takes a bit of torque to move them. But I think I'll be using the Central Valley turnout kits in the future and they move more easily. good luck!

  10. nwdstek

    nwdstek New Member

    Gary: Thanks for your good wishes. I'm afraid I must be a bit vague about my switch machine. It may be a marketable idea and require patent protection. I can list some of the features:

    1. Low cost ( very)
    2. Easy installation- compact unit mounts direct to bottom of switch. No additional linkage, no penetration of benchwork required.
    3. less wiring. Simple "on-off" circuit required to be fully operational.
    4. Low energy action is easier on switches. Doesn't slam like twin coils yet reaches full travel in less than 1/2 sec.
    5. Light point to stock rail pressure helps prevent derailments. Weight of train will move points allowing passage of wheels if switch is accidently set against routing of train.

    I call it " The cheapest, easiest, switch machine you will ever see, guaranteed, period, amen!" I have shown it to a few friends and business associates and the reaction so far has been favorable. What remains is designing a 1.5v power circuit to install on my layout and some months of testing to determine reliability. This should be interesting.
  11. Gary Pfeil

    Gary Pfeil Active Member

    Well, I certainly respect your need to keep a lid on the details, but I'm mighty curious about one of the selling points you listed. Are you saying the linkage, which mounts below the turnout itself, doesn't require a hole in the roadbed? Hope you can tell me how that's possible without spilling all the beans. The point about simple on/off circuit makes me think the turnout defaults to one route, presumably the straight or main route, unless power is applied to throw to the other route? Thus power is supplied as long as the thrown route is selected and can be a simple toggle switch (for those of us who use DCC but don't throw turnouts with it) whose lever position would indicate the route selected. And even if power is supplied you can run a train thru the other route and move the points? Would be nice and I think you'd find a market although it seems likely folks would build their own once they see it. But, I'm getting ahead of things. I do look forward to seeing what you've come up with when the time comes.

    Cheers, Gary
  12. toopoor

    toopoor New Member


    Maybe its me or my rolling stock. But when I run a train thru a switch backwards, almost always one of the rolling stock will derail. Whether it be pressure or the switch machine, I have some machines that are not connected and the rolling stock sometimes will derail. If I lower the speed that makes for a good transisiton, but at higher speeds I think you are asking for trouble if you don't switch that turnout to the correct direction. Now my loco's don't have any problem running thru the switch machine in either direction, and I usually don't switch the machines in the yard if not moving rolling stock. My point is even with no pressure on the points I can get a derail from rolling stock running thru it backwards, so light pressure would do the same thing or be worse. I would rather switch the point, before running thru the turnout backwards, gaurentee myself a good path, rather than risk a derail. Basically I like the tight pressure on the turnouts, as it gives me a piece of mind that i can run a train thru there at any speed and it will not move. Tortiose does this the best in my opinion.
    Just my .02.
  13. nwdstek

    nwdstek New Member

    Sorry to hear that you've been having problems. I would have to agree with your guess that your rolling stock is at fault. Out of guage wheels, worn bearings, bent truck frames, binding bolsters, and binding coupler shanks can all cause derailments. Bringing all your rolling stock up to NMRA standards is always a good idea regardless of what your track configuration is and can usually be done for a very modest cost.

    While doing development testing of my system I ran an old time 5000 gal. tank car which was within NMRA standard except for the weight (about 1.5 oz) through a spring equipped #6 Atlas switch against the points over 200 times with NO derailments. I did this deliberately to determine how an underweight car would react. After the testing period I added weight to the car to bring it up to spec.

    If you have been following this thread you will note that I came up with this system to save money and effort. I am building a club sized layout which will have 200+ switches when completed. This will amount to a savings of literally thousands of dollars. I presented my idea on this forum because I wondered if others would enjoy saving money and time as well. So far the response has been rather negative. If you all like paying $8.00 to $20.00+ ea. to operate your switches, enjoy! My cost for materials is less than $1.00 per switch.
  14. theBear

    theBear Member

    I'm not so certain that the response has been negative.

    Fred was trying to see why DCC brought forth a lesser need for good electrical contacts (it does precisely the opposite).

    Sorry operating from memory here only one browser window open, one other party was asking what was busted about the other means of moving points (from what I understand nothing is busted, it is only expensive).

    These folks didn't say your method was bad.

    As for me I'm all for a cheaper [​IMG] way of moving the points, however I'm one of those open source types who replies to most threads like this with a fine, now, show me the code or in this case have you got a picture of one operating we can see [​IMG] .

    Now that all said, does your method also allow for signal controls? Which is very important to me. I like lots of lights [​IMG] when I turn my Christmas tree on lights in 5 surrounding towns dim [​IMG].
  15. nwdstek

    nwdstek New Member

    It's going to take a little research, but I think signal controls could be incorporated. The motors I'm using have one grounded brush, and the armature shaft which the metal actuating lever is attatched to is grounded through the bushing so the motor itself might be used as a switch as long as the lighting circuit didn't go through the commutator.As for displaying an image, I understand your attitude about it. I would feel the same way. The problem is, I still have some hopes of making some money with this idea and it's so damn simple that would give it away. I plan to talk to some marketing people in the near future. If they convince me it's not a marketable idea, I will place it in the public domain.
  16. toopoor

    toopoor New Member

    All my rolling stock conforms to NMRA standards for wheel gauge and weight, and the only time they derail is thru the switch backwards without the points aligned correctly. If it was a rolling stock issue I would expect it to fail intermittantly in either direction, not only when the points are not aligned.

    I wasn't trying to be negative to your idea, just expressing an opinion that may save you some trouble of research and such. Part of proper operations is having the points aligned correctly.

    Beleive you me, I am all for cheaper equipment, but also for reliable operation. Having to switch out all my switch machines so I can run thru the turnouts backwards without aligning the points just doesn't make much sense to me since I have turnout control and can easily flip the switch to align the points correctly.

    my whole point to repling was I would hate to see you put all this time and effort into something that most users don't see a need for. I am one of those users. I would prefer the points be held tight, rather than lighter just so I don't have to throw a switch. The exact reason i invested so much money into the Tortioses is because of the stall motor and how it holds those points really really tight against the rail. That and the ability to add LED's for turnout indicators on the control panel. All that to me is worth way more than the 13.00 dollars a tortiose I pay.

    My hope is you do find alot of people interested in your product and are able to make money from it. Just wanted to proviode you with R&D from both sides..

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