A Trainboard Challenge!! Let the braintrust design the perfect coupler!!

oldrk Feb 8, 2011

  1. Metro Red Line

    Metro Red Line TrainBoard Member

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    We may not agree on how couplers are mounted, but we do agree that however they are mounted, they should not slink! :)
     
  2. mtntrainman

    mtntrainman TrainBoard Supporter

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    Ahhhhhhhh true...but can we also agree...that other then 'slink'...MT's are damn good couplers? :tb-wink:
     
  3. Metro Red Line

    Metro Red Line TrainBoard Member

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    They're reliable yes, but that two-piece shank still bothers me though! :)
     
  4. kmcsjr

    kmcsjr TrainBoard Member

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    Forget the coupler redesign (for now). Focus on a standardized coupler box going forward. Not all of the car makers will be willing to buy anyone elses couplers as it would drive up thier costs. Locos will be inherently more difficult, but it's the only thing that will work. This will only mean our new stuff will be universal. A fix for the past is impossible. Read on, if you want.

    I don't want to hijack the thread, but I think we should focus on world peace....

    Ya see, on the if I like it, I buy it (when I can afford it), then I run it on a few loops. ie: I'm stuck out of town on business and there Is a loop on the desk running the 10 smoothside Amtraks behind a Kato E8. For those I'd like to be able to couple them a little closer. Inside that loop a Bmann B&O 4-4-0 (don't laugh, after all my whining, it's pretty quiet) pulling 4 B&O Athearn Overland cars(they roll well with FVM wheels). These need body mount Z s to close the distance. The tender on the 4-4-0 will need an MTL. Around the TV, I was running a Minitrix Glaskasten, but I broke the Chimney when I went to tweak the gears. That could use different couplers, but all the cool "Eurostuff" has so many funky ways of attaching the Rapidos, that.... ah well, Rapidos are nice enough. I just ordered Scharfenbergs for some Japanese passenger stuff as even when I get to a layout, I hope to park passenger consist on sidelines. The Bmann 2-6-6-2 running around the TV now, has whatever Bmann uses for a knuckle coupler. Once it's pulling stuff, I'll decide if it is good enough.

    My problem isn't a new perfect coupler, as I like old stuff and no one is going to redo old stuff, with a new coupler. Even if they do, will you rebuy everything? The problem is taking the time to make all the old stuff work where I want it to. If I take the time, I can do most of it. For the rest I will use whatever is there. There will never be a truly universal coupler that fits all the funky places we put couplers, as there will never be universal agreement on the perfect coupler.
    After what I've read about all the existing knuckles, the MTLs seem to win. Will MTL engineer out the slinky effect to get thier coupler into all those coupler boxes? Did anyone redo a bunch of rolling stock with McHenrys, only to regret the flying springs? If so, will you standardize on the next great coupler.

    A universal box though would allow each persons to install the "best coupler". Then companies will compete to design something better as I would buy the better ones, if I knew I didn't have to alter and damage stuff to try the next great thing.
     
  5. steamghost

    steamghost TrainBoard Member

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    Slinky is not something that the 1:1 railroads want to happen, but it has happened. When cushion underframe cars were put together in groups, the middle car(s) would slinky and pulverize their cargo. The cushioning was too flabby . The solution was just to break up the strings of cars (into 2s and 3s IIRC) which then added the problem of more switching.

    So there you have a real-life not-perfect solution. It's already been shown that taking an Accumate coupler and putting it in the box on a MT truck negates the slinky effect:Kiss the dreaded Micro-Trains slinky effect goodbye - TrainBoard.com
    You do this for your caboose or EOT car, add weight. The belt-and-suspenders guys would also add the retarder springs. If you have slinkies mid-train, find the offending couplers and replace them - too much slack in em. That's not hard. If kermat13 won't take those at a quarter a throw, I will (though I think he might).

    One important thing for consideration is the material. You say "metal", but which metal, what composition? Engineering plastic may even be the solution but there are different formulations there. No coupler made of that matches MT for rigidity, though even that material gives (doesn't break but flexes so the knuckle opens) in a Z scale coupler when you have a train of about 50-60 cars. So what metal do you propose that won't crack or permanently bend is such an application, that can be cast or formed without further machining?

    The other concept that hasn't been broached is price point. What are you willing to pay for the perfect coupler? I'll bet it's not a lot, meaning not more than MTs.
     
  6. OC Engineer JD

    OC Engineer JD Staff Member TrainBoard Supporter

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  7. kermat13

    kermat13 TrainBoard Member

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    Steamghost--I am only buying his flawed coupler junk to help him out--when your converting cars you need to have the funds available to upgrade. Just think what a sucker I am buying his junk.
     
  8. brakie

    brakie TrainBoard Member

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    Slinky is not something that the 1:1 railroads want to happen, but it has happened. When cushion underframe cars were put together in groups, the middle car(s) would slinky and pulverize their cargo. The cushioning was too flabby . The solution was just to break up the strings of cars (into 2s and 3s IIRC) which then added the problem of more switching.
    --------------------
    Actually a lot of slack action was caused by a engineer wanna be that should have never been placed in the right hand seat.Of course these clods don't last long.

    The MT coupler is not perfect and has a design fault that many gladly accepts and adds band aid fixes and that's fine and dandy but,I have reach the point where I won't be shelling out hobby dollars on MT couplers and will slowly change 'em to the Atlas/Accumate combination since there isn't a slinky problem and they work well for me..My MTs will go to the trash can where IMHO they belong until they are redesigned.
     
  9. Carl Sowell

    Carl Sowell TrainBoard Supporter

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    I still say, wait for BLMA to produce an acceptable coupler.

    It really doesn't matter who comes up with one because they won't produce enough to satisfy the market ! They will be cautious with first productions to see how they are accepted. Why not make some prototypes and hand out to some of our highly talented N-scalers to test?

    Carl
     
  10. brakie

    brakie TrainBoard Member

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    Carl ,I agree a company will step up to the plate and make a reliable coupler in N and I suspect it will be similar to the HO KD coupler (like the current McHenry coupler) which is a solid and well proven design that been around 50 years and is HOs de facto standard coupler...

    Guys,My dislike for the slinky coupler didn't happen overnight..

    Again I was switching cars on the DT RR and I stooped down to watch my NS GP38 pull 7 cars by the switch-a beautiful sight until the last 2 cars came by slinking back and forth and as I mention POP! went all believability of being trackside watching a GP38 switch cars.

    Needless to say I found that unacceptable and started field testing couplers and the Atlas/Accumate seems to be what I need...Until something better comes along.

    I found the McHenry to be a fairly good coupler but,they give a unacceptable break in two while passing over magnets.
     
  11. kermat13

    kermat13 TrainBoard Member

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    But your grand-childrens childrens, children will celebrate you as a recycling pioneer by selling those couplers to someone who will recycle them rather than them landing in a landfill. Seeing as how they are MT couplers, they probably will never decompose. :pbiggrin:
     
  12. SteamDonkey74

    SteamDonkey74 TrainBoard Supporter

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    I had thought we were designing the ideal coupler, not simply trash-talking the ones we already have. Anyone else have a coupler design or some design parameters. I think we can all agree that the slinky effect isn't desirable, so lets agree on that one and put it to bed if we can.
     
  13. Grey One

    Grey One TrainBoard Supporter

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    No-one else interested in draw bars and a special coupler design for unit trains?
     
  14. kermat13

    kermat13 TrainBoard Member

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    I have cut Rapidos down to make draw bars--worked well--just didn't like my storage options for them and changed to unimates/red caboose couplers
     
  15. Metro Red Line

    Metro Red Line TrainBoard Member

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    Or an N-scale working rotary coupler!
     
  16. Charlie Vlk

    Charlie Vlk TrainBoard Member

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    I somehow missed this thread. I ran into Mark Hinds at Des Plaines Hobbies this Saturday and he mentioned it to me.

    Since I was involved in (but not entirely to blame for !!) the design of the Kato Magnetic Coupler when I worked at Kato USA, this is a subject near and dear to my heart.

    I copied over the text of the entire thread to a document and will offer some comments on the points raised. Some preambles to set the stage:

    Kadee and Keith Edwards helped make N Scale what it is with the Micro-Trains Magnetic Coupler. Prior to that, the adoption of the Arnold Rapido coupler enabled N Scale to become a commercial success. At the Long Beach NMRA / NTRAK / N Scale Collectors convention in 1996 a panel discussion of N Scalers and Manufacturers decided that it was time to move away from Rapidos and towards converting over to M-T compatible couplers. Atlas licensed an N Scale version of the Accurail Accumate and Kato developed a number of semi-automatic and finally a magnetic coupler of their own design. Today, in 2011, all major brands finally have some form of M-T compatible coupler on their equipment.

    Existing available N Scale knuckle couplers:
    Micro-Trains
    Accurail
    Kato
    Mc Henry
    Bachmann
    Red Caboose (Precision Masters Dummy)
    Con-Cor (M-T dummy clone)
    Korea/China OEM (M-T / Accurail hybrid)

    As I write this there were 95 previous posts on this thread. I am not going to address all the comments but concentrate on the technical issues raised:

    1. Any coupler that is introduced to the general market must be compatible with existing couplers. It is not practical to develop a proprietary coupler that requires conversion of all equipment.
    2. While a radically different basis of functioning is possible (individually addressed electronic uncoupling, mechanical or different magnetic method) the magnetic uncoupling trip pin is practical and established technology….if some issues can be worked through.
    3. The NMRA or any other group cannot be counted on to standardize coupler or draft gear dimensions. Even if some group attempted to do so the marketplace is the best arbiter of product design…..(items 1 and 2 above are dictated by real world market conditions).
    4. The installed base of equipment in the hands of N Scalers must be a consideration in the design of any product if it is to be successful. The M-T is the defacto standard in N Scale even if it is not so recognized by any organization and certainly the MT-1015 is the most universal of the many styles of Micro-Trains couplers.
    5. The Micro-Trains coupler is clearly still the market leader. For cost and supply considerations the “clones” have enjoyed some success and having them on equipment out of the box is better than totally incompatible Rapidos. M-T continues to be the leader in the separate sale Coupler and Truck aftermarket and offers a wide range of coupler conversions for specific locomotive and car mounting situations and this is not likely to change in the near future.
    6. There are, however, several issues with the M-T coupler design that have been raised here:
    a. Appearance – the shape and detail of the M-T coupler looks very little like a prototype coupler
    b. Size – the M-T coupler is grossly oversize in mass, height, width, and length
    c. Operation – most M-T couplers rely on a free-floating central coil spring for centering and closure. This allows the dreaded “slinky” effect which can cause false uncouplings. Many N Scalers do not appreciate the work-around of drag springs on wheelsets to keep the slack stretched. The general design has been modified by the “RDA” in an attempt to counter false uncoupling on long trains.
    d. Strength – Some concerns have been raised on the strength of M-T couplers, primarily in rough service on very long trains. The thin M-T profiles of the knuckle and guard arm may contribute to this.
    e. Tolerances - Existing M-T couplers have excessive slop in the tolerances of shank thicknesses, fit into coupler boxes, etc.. which contribute to mis-alignment of couplers even when properly installed.
    f. Uncoupling – Because the magnetic couplers have to rely on a fixed permanent magnet between the rails or underneath the ties, false uncoupling is common and limits the use of the automatic uncoupling feature to the point where many use manual uncoupling with some even cutting off the magnetic trip pin. Electromagnetic coil uncouplers would solve the problem but they are expensive and too bulky for widespread use and require extensive modification of the roadbed to install.
    g. Draft gear boxes are too thick / long / wide for many mounting situations.
    h. Truck mounted (“Talgo”) draft gear clearances require raising the carbody unrealistically high over the trucks and/or cutting away floor/car ends to clear them.
    7. Other brand N Scale and HO couplers address some of the issues but each introduce new problems, especially when rendered in N Scale:
    a. Appearance - none equal the improved prototype fidelity of the models they are intended to be mounted on.
    b. Size – because of the requirement to couple with the M-T, all are oversize in mass even if some of the excessive slop in overall size is tightened up.
    c. Operation – alternative methods of centering using integrally-cast engineering plastic springs have not been successful in practice. Closure using this method is also not reliable and using Kadee #5 separately sprung knuckles results in a vulnerable tiny yet unrealistic coil spring.
    d. The Sergent coupler is an interesting concept but has enjoyed a very limited market in HO due to incompatibility issues with other brands.
    I cannot see scaling it down to N resulting in a reliable coupler… the
    physics involved (gravity, tooling tolerances) work against it in 1/160 and
    smaller scales.
    e. Having lived through the evolution of the Kato knuckle coupler from the previous 11-701 (original smoothside passenger car and first production E-8) to the near-scale rear coupler of the business car, the disastrous semi-automatics on the second production smoothsides and corrugated passenger cars, to the almost great Kato magnetic automatic coupler, I have some insight into what needs to be in a coupler. The horrible semi-automatic couplers, when they did not fall apart or jam open, because they were close to the overall size of a Z-Scale coupler, did not have enough vertical gather (height) to stay coupled on the typical horrible track standards on an NTRAK setup or some home layouts. I know that many use M-T Z Scale couplers to get better size, but this use is limited to a small segment of the N Scale community and is forced because there are no better alternatives.
    With all due respect to those proposing the Bowser OEM Z-Scale coupler, it, too, is a compromise stopgap and is not our salvation, especially since it is essentially a improved small version of the Accumate.
    8. Plastic vs. Metal - Some have raised the issue of making the couplers out metal instead of (engineering ) plastic. The practical impact of making N Scale couplers out of diecast metal or investment cast / coined parts is not proven, but I suspect that engineering plastic is stronger in the small cross- sections involved and perhaps better for less friction in sliding mating surfaces.

    I believe that ALL of the technical issues with existing couplers that have been raised can be addressed…. as well as additional ones that have not been brought up here.

    The only issue, as one poster pointedly observed, is “I personally would love to be able to re-equip my fleet before I die... “

    Charlie Vlk
    Railroad Model Resources
     
  17. jpwisc

    jpwisc TrainBoard Member

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    I concur, I'm hearing lots of problems, but not seeing any solutions. Do we have any mechanical engineers that could CAD a better design?

    Con-Cor just released a new coupler just for unit trains... Rigid Jaw
     
  18. kermat13

    kermat13 TrainBoard Member

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    Very nice--but almost twice the cost I can get MT couplers and trucks in bulk
     
  19. SteamDonkey74

    SteamDonkey74 TrainBoard Supporter

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    I can't figure out what the big deal is on the Rigid Jaw. Weren't non-operating couplers the technical limit 20 or 30 years ago? They're treating this as if it is a new thing. Maybe it is. I haven't been in N scale long enough to tell.
     
  20. Grey One

    Grey One TrainBoard Supporter

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    Cool! - um, where do I get these?

    Charlie Vlk - Thanks! for a great post!
     

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