N scale close coupling alternatives

NorsemanJack Jul 6, 2018

  1. NorsemanJack

    NorsemanJack TrainBoard Member

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    Here's a side by side comparison of MT Heavyweights with Z scale 905 couplers and Micro-trains True Scale Couplers:

    Micro-trains Z scale 905:

    Micro-trains True Scale Couplers:

    To my eye, and also to my calipers, the improved coupling distance is the same in both cases. The True Scale's are a bit nicer in appearance (and also a bit cheaper), but they won't work well for anything but the widest radii (think 30" plus). They are noticeably restrictive around a 17.5" radius (i.e. the curve forces the couplers to rotate on their mounting pins in order to navigate the curve).

    Also, we've learned in another forum discussion that the MT heavyweight diner has different coupler mounting dimensions than the rest of the Heavyweights. I measured the mounting holes to be approximately .060" further from the car ends than they are on the other variations. This means that they aren't as "bad" as the other cars, but are still very wide in coupling distance. I won't have photos until I obtain some more 905's.

    Joe: do you know why the diner is different?
     
  2. bremner

    bremner Staff Member

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    Micro Trains True Scale Couplers look great, and are an option. I have 2 locos and about 8 cars with them and I can switch my layout with them.
     
  3. NorsemanJack

    NorsemanJack TrainBoard Member

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    What is your tightest radius?
     
  4. bremner

    bremner Staff Member

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    Um......big
    [​IMG]
     
  5. NorsemanJack

    NorsemanJack TrainBoard Member

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    LOL. Thanks. You mentioned that "true scale couplers are an option," which prompted my question. I mentioned them in the very first post of this thread, and we've touched upon them several times. I think it is reasonable to add the qualification that they are an option only for people with VERY broad minimum radii. Otherwise, they really aren't an option.
     
  6. scottryan

    scottryan TrainBoard Member

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    923500 are not the correct short shank couplers for the DCC friendly SD45.

    The correct ones are 923503
     
  7. NorsemanJack

    NorsemanJack TrainBoard Member

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    I believe you are mistaken. The 923503's are unique to the NW2 according to Kato's parts website. I am certain that it was the plain old 923500's that I swapped for the medium shanks in the latest SD45's. See my photos earlier in the thread.

    Why do you think that the 923503's are correct? They appear to be a much different coupler.
     
  8. scottryan

    scottryan TrainBoard Member

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    I'm not.

    The DCC friendly SD45/C30-7/U30C, GEVO, SD70ACe, and retooled C44-9W use straight shank couplers. These locos come from the factory with 923502 medium shank straight shank couplers.

    The 923503 are short shank, straight shank couplers. They come on an NW2 but are not specific to the NW2.

    If you place a 923500 in the locos above I mentioned, the coupler will sit too high when compared to an MTL height gauge.

    923500 (offset shank) are used in the SD40-2, SD80/90, SD70MAC, original run C44-9W, retooled DCC SD40, and some others.

    If it came from the factory with an offset shank, the 923500 is the correct short coupler.

    If it came from the factory with an straight shank, the 923503 is the correct short coupler.
     
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  9. NorsemanJack

    NorsemanJack TrainBoard Member

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    Thanks for that explanation. I see it now. Not sure how far "off" my SD45's are in height, but those medium shank couplers just looked ridiculous. It looks like Kato is sold out of the 923503's, but hopefully they'll restock at some point. I guess we could always use the 923500's between units and on the pilot, but stick with the original 923502 for the trailing unit.
     
  10. NorsemanJack

    NorsemanJack TrainBoard Member

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    Here is the photo of how far "off" the 923500 is on the SD45. Not ideal, but apparently close enough to stay coupled on level track (I've used these to pull long freights of MT cars and never had any uncouplings. I'll still swap to the 923503's if/when Kato restocks. Those medium shanks just look silly on these locos.

     
  11. SF Chief

    SF Chief TrainBoard Member

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    Once again, it seems that the answer to any question worth asking is "it depends."
    Rick
     
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  12. NorsemanJack

    NorsemanJack TrainBoard Member

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    Yep. I do appreciate Scott educating us on this. I'm currently trying to acquire some of the straight short shank Kato couplers for comparison purposes. I'll post photos if/when I'm successful. If it helps us with our efforts to get rid of silly coupling distances, I'm for it!
     
  13. NDave

    NDave TrainBoard Member

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    After following this thread for some time, I decided to try close-coupling my MTL heavyweights with MTL 905 Z-scale couplers. I ruled out true scale couplers, because my min radius is a smidge under 17", and the cars also would need to negotiate #7 turnouts... didn't seem that the Truescales would work well with these limitations. I thought my experiences might help someone out...

    The good thing, it's a very simple swap on all but the dining car... using the same holes and pins that were used to mount the factory couplers. I bought 3 packs of the MTL 905s, sufficient to change out 6 of my 7 cars... leaving the diner til later, since it would require drilling new holes.

    I must say, I was a bit disappointed with first runs of my now "close-coupled" passenger train, pulled by my Kato FEF-3. Although the close-coupled cars looked great and negotiated all my turnouts and curves just fine, there were multiple "random uncoupling events (RUEs)" with each trip around my twice around layout. I check all the coupler heights, and they seemed good... The RUEs did not occur passing over turnouts or track joints, or at the transition point in a in grade. They did not seem to result from uneven track. Finally, after a couple operating sessions, I began to notice a pattern. The RUEs consistently occurred in two specific circumstances: (1) when pulling the cars on any downhill turn to the right at road speeds (40-45 smph), or (2) when slowly pushing around a right turn that transitions from level to downhill, a group of cars might uncouple and coast down grade in front of the train.

    When inspecting the couplers, I noted that right hand turns tend to move the knuckles linking two cars away from each other. When combined with the inevitable slinky action of MTL couplers at road speeds running down grade, this caused the RUEs: as the trailing car sped up and bounced its coupler against the leading coupler in a right turn, they uncoupled. Similarly, at low speeds, pushing around a right turn the couplers are in compression while the right turn works to uncouple the knuckles, and if the train then enters a down grade, a runaway results.

    I THINK I have come up with a two part solution, that has allowed me to get through two operating sessions w/o a single RUE:

    First, I turned each coupler slightly off the cars axis... looking from above the car, I twisted each coupler ever so slightly counterclockwise on its mounting pin. This should cause the knuckles on the two cars to stay better engaged in right hand turns. This seemed to help reduce the frequency of RUEs, but did not completely eliminate the problem.

    Second, I added one of the "truck restraining springs" supplied with the couplers to one axle on each of five (the last five in the train) of my seven cars (I will probably add a spring to one axle of each car, eventually), hoping to reduce the slinky effect. This seemed to have the desired result... slinky isn't completely eliminated, but it does seem reduced, and no RUEs since. Although adding the axle springs will reduce the number of cars that my FEF-3 can pull, I only have 7 heavyweights right now... and the FEF-3 easily pulls them all (with springs on 5) up the 1.8% grades on my main line. I doubt that I will ever pull more than 8 heavyweights, as that is all my spur passenger track can accommodate (and my main line just isn't long enough).

    Anyway, I thought I would share MY experiences... I am hoping that I have eliminated the random uncoupling. If so, I'll get another pack of 905s and swap out the couplers on my diner.
     
  14. NorsemanJack

    NorsemanJack TrainBoard Member

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    Thanks for the report NDave. When I first converted a few Heavyweights, I found that I could make them uncouple by using a push/pull motion (nothing really intentional, just using my hand to couple and test the connections). Those Z scale couplers have much less height, so easier to cause one to slip over or under its mate. With some judicious shimming (outlined earlier in the thread) I was able to eliminate that for the most part. I haven't had any uncouplings while pulling them with a loco. I've got a restock of the 905's coming, so will be able to complete an entire train (~9 cars I believe). It sounds like the grades on your layout are a contributing factor. My layout is perfectly flat, so I don't suffer from much up/down slinky effect. I'm sure there are also some "hit it with a sledge hammer" approaches that would reduce/eliminate any issues. The smallest dab of Liquitape inside the coupler knuckle would likely make them hold on like they never wanted to uncouple.
     
  15. NorsemanJack

    NorsemanJack TrainBoard Member

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    Update on an old thread. Kato USA is still sold out on straight, short shank couplers (#923503). Fortunately, there is a Japanese version Z01-0224 that appears to be identical except for the absence of a hole for the magnetic coupling pin (which many of us never install). That Japanese version is available in black, grey and several other colors. I was able to obtain a number of these through ebay. I'll upgrade my SD45's and post pictures when I get around to it. :whistle:
     
  16. Inkaneer

    Inkaneer TrainBoard Member

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    I am not a fan of body mounting couplers. My passenger consists are the older Concor smooth side cars with truck mounted couplers. I kept the Concor trucks but swapped out the wheels for (I believe) Intermountain 36 inch wheels. The cars rolled much better with the new wheelsets. For couplers I used Kato 11-702 couplers which may have been discontinued. This coupled the cars within a hair of the buffers actually touching. Cars could negotiate tight curves with out derailing but the couplers do not seem strong enough and will disengage even on straight level track. Thinking of going to Unimates but first I got a package of Tomix couplers that I want to try.
     

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