MTL couplers and the "inchworm" (slinky) effect

Mark Truelove Jul 15, 2021

  1. CSX Robert

    CSX Robert TrainBoard Member

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    Slinky with a three car switching movement:
     
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  2. Doug Gosha

    Doug Gosha TrainBoard Member

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    It looks pretty minimal, to me.

    Doug
     
  3. acptulsa

    acptulsa TrainBoard Member

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    Maybe. But I've seen HO cars stutter that much (or nearly so) crossing a frog, and that must be coupler slack allowing it.

    Of course, I know of no way to separate a tiny bit of spring compression from simple slack. And whatever it is, I'm not motivated to eliminate it, because I'd swear I've seen short cuts of 1:1 scale empties do that crossing a frog.
     
    Last edited: Jul 26, 2021
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  4. BarstowRick

    BarstowRick TrainBoard Supporter

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    I see what you see in the video and have never thought much about it. About as close to Slack as you are going to get. The bounce back and forth bothers me. Just... Not enough to change up my loyalties.

    The difference between the real McCoy and our scale trains. The brakes are either activated by air or a brakeman has turned down the brake in one of the cars they are switching. We can't do that except to increase the drag coefficient between the truck and wheelsets.

    On the 1:1 scale. I've also seen this kind of action in a short string of cars being transferred from one end of the yard to the other. You know, close enough to call it.

    I honestly think MTL has done very well to attempt to capture the Slack Action. Yes, I agree it's a bit over-exaggerated. I wouldn't want to see them change it. Then who would I have to go to, to find such action. If you know what I mean.


    Now with that said. I need to get back to my 40 and 50 car freight trains. I need to get them running again. Sigh!!

    Later.
     
    Last edited: Jul 26, 2021
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  5. CSX Robert

    CSX Robert TrainBoard Member

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    Yes, that's pretty minimal, but visible and, at least to me distracting. If you have that going on between several cars of a multi-car cut, that last car can bounce around quite a bit.

    I don't see that much stutter between two Accumate or two Mchenry equipped cars.

    For starters, the spring compression has a rythmic "bounce" to it that slack does not.
    It's hard to measure precisely, but I estimate the slack plus the "tiny bit" of spring compression between two microtrains equipped cars to be about 2.5 - 3 times the slack between two Accumate equipped cars.

    Well, good, I'm happy for you. Some people it doesn't bother, others it does.

    I have never seen 1:1 cars come even close to what I've seen Micro-Trains equipped cars do. It's not the occasional cars bunching up or spreading out but the rythmic bouncing. It's the difference between an automobile with good shocks and one with worn shocks traveling down a bumpy road. Yes, the wheels on the one with good shocks are going to travel up and down over the bumps, but they don't have the rythmic bounce afterwards of the worn shocks.
     
  6. acptulsa

    acptulsa TrainBoard Member

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    Well, I admit, it's easy to have a cavalier attitude about it since I model HO...

    :whistle:
     
  7. Shortround

    Shortround TrainBoard Member

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    This discussion brings back memories of one of my 'Choppers'. A custom built frame with '48 Indian rear suspension. Three inches of coil spring above and one inch below the axle. No shocks. Nicer than a hard tail and some passengers liked it.
    But never noticed it on my last running N gauge models. Just in the switching yard across the street.
     
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  8. Inkaneer

    Inkaneer TrainBoard Member

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    On the contrary, it is an excellent option especially when you factor in cost of replacing couplers. But, hey, it is your RR so MRR Rule #1 applies.
     
    Last edited: Jul 26, 2021
  9. Inkaneer

    Inkaneer TrainBoard Member

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    What I noticed in the video was that the locomotive's acceleration was not smooth and a bit on the jerky side. That did not help at all. I'd be interested in knowing if those cars were weighted to NMRA recommendations. Regardless, MR Rule #1 applies and if you want to change couplers to something else then by all means do so.
     
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  10. mtntrainman

    mtntrainman TrainBoard Supporter

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    What 'SLINKY' ???????

    1) Smooth running locomotives. (y)

    2) Clean wheelsets. (y) Clean track. (y)

    3) Properly weighted rolling stock. (y)(y)

    4) Excellent track work. (y)

    5) Bad eyesight. ( slinky is hardly noticable at all !! ) ;)

    6) Always watch your trains coming at you...or going away from you. NEVER from the side ! :whistle:

    7) :coffee::coffee::censored::censored::coffee::coffee::censored::censored::coffee::coffee::coffee::coffee::coffee::coffee::coffee:

    8) Rule #1 !!!

    .
     
    Last edited: Jul 26, 2021
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  11. Doug Gosha

    Doug Gosha TrainBoard Member

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    I don't see how a small amount of the slinky action can be THAT distracting. I mean, we all know we're playing with model trains. We can't expect them to mimic the prototype perfectly, can we?

    Doug
     
  12. BigJake

    BigJake TrainBoard Member

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    Yep, slinky action is pretty low on my prioritized list of model railroading things to worry about.

    And that list is pretty low on my prioritized list of lists of things to worry about.

    I didn't get into this hobby to have yet another thing to worry about!

    It is a "no worries" activity for me.
     
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  13. Shortround

    Shortround TrainBoard Member

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    Is this what those big bumpers are for on European trains?
     
  14. CSX Robert

    CSX Robert TrainBoard Member

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    Well, first of all, I don't find the amount of slinky in that video "THAT" distracting, it's a little distracting, but something I could happily live with. The whole point of the video was just to show that yes, slinky does occur on even very short trains, which some didn't seem to believe. Now you get that going on between several cars in a longer train, often adding together, and it does become "THAT" distracting, in fact to me and to many others very distracting.

    Secondly, there are probably hundreds of things on a model railroad about which you could say "I don't see how it can be THAT distracting, we all know we're playing with model trains." Just a few things that I've heard some people complain about that many others don't care anything about:

    Wrong prime mover sound or horn sound on a sound equipped loco.
    Slightly off prototype colors.
    One loco posing as a close but slightly different other one(i.e. that "GP38-2"is really a GP38 because it doesn't have a water sight glass).
    Wrong driver size on steam locomotives.
    Car or locomotives painted for railroads that never had them(personally, I like my CSX turbine).
    Code 55 vs code 80 rail.​

    The list goes on and on. We're all different in what we care and don't care about, but if we all had the "I don't see how it can be THAT distracting, we all know we're playing with model trains" attitude about all the little details, we could just push Brio trains around going "toot! toot!"
     
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  15. NtheBasement

    NtheBasement TrainBoard Member

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    I agree with much of the above. I'm a big fan of MTL truck-mounted couplers. I've never had an operational problem such as unwanted uncoupling because of it, but I can see how that might happen over a permanent uncoupling magnet. The bounce is most visible but irregular at slow speed. Sometimes its more pronounced like it it gets a positive feedback effect going at specific higher speeds.

    As to how much I care, I didn't even notice it until someone discussed it on a forum. However, if I was making a video to show off my layout I would cut out any footage that had bouncing rear car(s) in it.

    I have a firefly fred and the friction caused by the electrical pickups is more than enough to completely eliminate the bounce.
     
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  16. CSX Robert

    CSX Robert TrainBoard Member

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    I really don't see how you could consider it "an excellent option" in the situation that I described. In many situations it is, but not this one. If you want to be able run any car at the end of the train without changing out axles or trucks, then you'll have to add extra resistance to every car, which will have a major impact on the length of train a locomotive or consist can pull. If you only add resistance to the last car, it will have very little effect on possible train length, but you can no longer run just any car at the end. So, if you don't want to limit train length and you don't want to limit what you run at the end, not only is adding extra resistance not an excellent option, it's really not an option at all unless you seriously compromise on one of the other stated goals.
     
  17. Inkaneer

    Inkaneer TrainBoard Member

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    Look, you are setting limits on yourself. Why??? If it bothers you so much that you obsess with it then switch out your couplers to whatever brand you want. Apparently the 10 foot coupling distance between cars equipped with McHenry's and Accumates doesn't bother you. Truscale coupler? Better have excellent trackwork. Unimate coupler? Excellent if you want to physically lift a car to couple or uncouple. How prototypical is that? Quite frankly, I think the downsides of the Accumate and McHenry coupler far out weigh their advantages. But that is me and MRR Rule #1 applies. But if you are intent on eliminating the "slinky" by the most expensive method possible then change out all your couplers and send all your MT couplers to me where they will be well received and I promise to provide them with a good home.
     
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  18. Doug Gosha

    Doug Gosha TrainBoard Member

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    Robert, except for your mockery, I agree with your post. many people take themselves way too seriously with model railroading. All six of your examples are fairly silly over which people obsess.

    You forgot the quintessential one, however:

    The number of rivets in a row. :D

    Doug
     
    Last edited: Jul 27, 2021
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  19. acptulsa

    acptulsa TrainBoard Member

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    Admittedly I don't have a dog in this fight, not modeling N. But this subject intrigues me, not least because I'm a fan of torsion bar suspensions in cars, and the (sometimes undesirable) characteristics of coil springs interest me. Would you mind keeping us posted?

    In terms of both the slinky action and more realistic spacing between cars, the foam looks promising to me. I particularly like the way it is springy in all directions, so it doesn't have to operate indirectly on the two sides to close the knuckle the way the coil does.
     
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  20. Doug Gosha

    Doug Gosha TrainBoard Member

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    The problem with foam, however, is that you don't know if the foam you use is going to last. A lot of it disintegrates and you will installing it again after a time.

    I do like torsion bars, however. I had a 1981 Cordoba (beautiful car) and, after a few years, the front driver's side looked like it was sagging a bit. measurements proved it. Instead of messing with shims or having a coil spring replaced, just went under there and cranked on the bar a bit and viola!...er...voila!

    Doug
     
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