Close-coupling Kato F units

Discussion in 'N Scale' started by NorsemanJack, Jun 20, 2010.

  1. NorsemanJack

    NorsemanJack TrainBoard Member

    Just a few photos of some experimenting I've been doing to improve the coupling distance of Kato F units:





    I'll post more info and photos if anyone is interested. The new couplers are Kato dummies, and the diaphragms are improvised using some off-the-shelf Kato parts and a fabric "filler." Total cost for a B unit is less than $3 and an A unit is under a buck and a half.
  2. AtomicVette

    AtomicVette TrainBoard Member

    I'm interested! That looks great!
  3. gregamer

    gregamer TrainBoard Member TrainBoard Supporter

    I was looking at a pair of Kato F7s last night and thinking that the coupling distance seemed redicoulous. I wish I'd seen this last night though, because I just placed an order with Kato, and I probably could have thrown in some of those dummy couplers.
  4. mrlxhelper

    mrlxhelper TrainBoard Member

    Is that Kato part #923090 ??? Also, do the roof points bump each other when the slack runs in like they do with short shank unimate's?
  5. atsf_arizona

    atsf_arizona TrainBoard Member TrainBoard Supporter

    Can you post some pictures of these "Kato dummy" couplers? Do you have a part number?

  6. riog66

    riog66 TrainBoard Member

    Great improvement, I wasn't aware of the Kato part you mentioned
    I had installed Unimates on my F3 A + B's but I like what you've done..especially with the foam block.

    Great stuff - thanks for posting :thumbs_up:
  7. r_i_straw

    r_i_straw Administrator Staff Member TrainBoard Supporter

  8. Flash Blackman

    Flash Blackman Staff Staff Member TrainBoard Supporter

    I've just put some American Limited diaphragms on my F units. I am very interested in your method and techniques.

    For close coupling on kato F units, I have used the Micro Trains conversion on one and a Unimate dummy coupler on the other facing unit. IIRC, the correct prototype spacing between the car bodies is four feet.

    [edit] That Russell Straw has parts for everything! :thumbs_up:
  9. Inkaneer

    Inkaneer TrainBoard Member

    The "T" shank Unimates were the close coupling coupler of preference as they came in three shank sizes. They were a drop in fit for units with truck mounted couplers like the Kato F7's and the early [plastic frame] LifeLike FA/B2's. The IM and later LifeLike units needed the body mount and required more work. Great for drawbarring an ABBA set together to preven uncouplings. Apparently the Unimates are in scarce supply. The Kato coupler looks a lot like the new Bachmann coupler. I got several of those on some spare tenders I purchased and from the limited testing I did they seemed okay but I did not have the opportunity to test them under the load of a long train ala Ntrak.
  10. NorsemanJack

    NorsemanJack TrainBoard Member

    That is the coupler I used. The packages now include ten couplers attached to a sprue, which comes in handy for painting. I wanted mine to be silver, so while still attached to the sprue, I gave them a bath in isopropyl alcohol and then spray painted them silver. I don't like the way the Kato spring fits with these, so before installation I've been lightly filing the back surface of the coupler (where the spring makes contact) and glueing the springs to the coupler prior to installation. I tried gel super glue, but found that Micro-scale Krystal Klear works better for me. I prefer to remove the shell during installation, as it makes it easier to get a small screwdriver in to pop off the original coupler cover (on top of the coupler pocket). After that, it's just a matter of twisting the original coupler 90 degrees to remove it and installing the dummy coupler with a similar 90 degree twist.

    The diaphragms are just Kato CZ parts that have had the mounting "ears" snipped down a bit, but not removed entirely (the remaining nubs make positioning on the locomotive easier). They are glued on using Krystal Klear, which seams like it could be removed later if so desired. The final addition is a piece of fabric that I found with my wife at a fabric store. It is grey automotive headliner and consists of a smooth grey surface with small ribs on one side and a black foam backing on the other. I folded it over so that there is a continuous grey surface with a rounded top and glued the two sides together. The result is a flexible, foam filled piece with a smooth grey surface on both sides and the top. Then I just trimmed it to fit with scissors and slipped it between the two engines prior to coupling. If it is examined under magnification it probably won't look very good, but I'm looking for a cheap, non-invasive way to add working diaphragms to passenger consists and this is a first attempt. Without the reduction of coupling distance, this wouldn't work. I bought a lifetime supply of this fabric for $1.06, so it is essentially free.
  11. NorsemanJack

    NorsemanJack TrainBoard Member

    That's the correct part number. It looks like the roof points can contact each other with these if the coupler change is the only modification. Addition of the diaphragms, either with or without the fabric "filler," prevents the type of contact you described.
  12. jmwinfield

    jmwinfield TrainBoard Member

    One question I have is, how about the distance between two A units run elephant style?
  13. atsf_arizona

    atsf_arizona TrainBoard Member TrainBoard Supporter

    I'd like to see the comparison between the older short shank Unimates
    and the Kato dummy coupler 923090, would be interesting for all of us to compare.

    For it's worth, here's a shot for comparison, of the older short shank Unimates
    on Kato F7s:


    And for comparison sake, I'd love to see what a side-by-side of the
    Kato dummy coupler looks like, compared to the Unimate short shank,
    which you can see in this photo (along with the 'stub' that must be left
    from cutting it off the sprue, in order to have the spring be able to slip over):


    You can see a photo album of photos of the Unimate on the
    Kato Fs/Es/PAs, that you are welcome
    to use for comparing to the Kato dummy coupler, at:

    kato_n_scale_unimate_install Photo Gallery by ATSF_Arizona John Sing at

    Hope this helps. Thx for bring the dummy Kato coupler to all of our attention!
  14. NorsemanJack

    NorsemanJack TrainBoard Member

    John - thanks for adding the info on the Unimate. With the Kato dummy, I didn't have to cut the angles on the coupler, as it twisted into the pocket just like a normal Kato coupler. I like your tip about leaving the small sprue stub on the Unimate to help keep the spring in position. With the Kato springs, they seem to function reliably without the stub, but as I mentioned in my earlier post, I've been glueing the springs on prior to installation to give a bit of added assurance that they'll stay in place for the long haul. It also occured to me that I could use the tip of a solder iron to heat the spring and "melt" it into the coupler a small amount, however I haven't tried that yet. That slippery black plastic will hold paint and glue to a point, however like the older MT coupler assembly process, a bit of heat to weld the pieces might be the best approach. I'm sure that as soon as I get everything converted, Kato will release these couplers in the silver/grey plastic so as to make all of my painting a waste of time. :tb-biggrin:

    Also. seeing that you're a Santa Fe fan, I'm curious if you might own the Green Frog DVD "Santa Fe Odyssey volume 1?" This is an outstanding video for viewing ATSF F units, E units and PA units in action. The Emery Gulash film work is unmatched (as usual for Emery). The reason I bring this up, is that I rewatched mine over the weekend hoping to gain some perspective on the presence or absence of diaphragms in the later years of service. I was surprised to see a number of F unit consists with the diaphragms in place into the early 60's (I believe that 1962 was the latest date mentioned). There was a nice 1958 clip of the El Capitan with a matched ABBA set of F3's, with diaphragms. I was surprised to see F3's on that train instead of F7's, but maybe a Santa Fe fan can shed some light on this.
  15. mark.hinds

    mark.hinds TrainBoard Member

    Nice job.

    BTW, to correct a statement made earlier in this thread, the prototypical coupled distance between A and B units (measured between the verticals of the respective carbody sides) looks to be 3 feet, not 4 feet. I base this on general observation, and on the Kalmbach Locomotive Cyclopedia, Volume 2, (diesel locomotives), where the distance is dimensioned as 18" to the inner face of the coupler. Multiply by 2 and you get 3 feet.
  16. NorsemanJack

    NorsemanJack TrainBoard Member

    It looks pretty good!


    Also, I would be interested in opinions on how the unit on the right looks with that passenger diaphragm hanging off the back. Does that look better or not?
  17. jmwinfield

    jmwinfield TrainBoard Member

    Thanks for posting the pic. Glad to see that running elephant style will work with the shorter coupling distance. My desire is to model the era where the Santa Fe frequently ran their F units elephant style, i.e. AABBA, or ABABBA lash ups, on the Chief, and El Capitan. I seem to recall that in later times, Santa Fe didn't use diaphragms between F units.
  18. NorsemanJack

    NorsemanJack TrainBoard Member

    Jim - I suggest you check out my comments in post #14 regarding the Emery Gulash films of Santa Fe F units in action. They provide positive verification of Santa Fe's use of diaphragms on F units into the early 60's, which is probably at retirement for many. I'll again recommend the Green Frog Santa Fe Odyssey volume I DVD for Santa Fe fans and railfans in general. To your point, there are some great shots of massive strings of F units pulling the Super Chief and El Capitan up the mountain grades. I remember one shot of an ABABBBA lash up. There's also a shot of a Santa Fe freight leaving Chicago with warbonnet dual use units in an ABBBBB (I think) configuration. Great stuff! :thumbs_up: I've accumulated four warbonnet A's and four B's plus the El Capitan and Super Chief sets to be able to replicate such consists. I'll likely be giving them all the treatment shown in post 1.
  19. NorsemanJack

    NorsemanJack TrainBoard Member

    Thanks for that info. After reading your post I also dug out a book with some diesel drawings and found F3, F7 and E9 drawings indicating that same 18". Interestingly, the dimension on the nose is only 9", so running elephant style actually results in the units coupling closer. I'm guessing the 4 feet posted earlier came from the geeps, as those drawings indicate 25" from end of carbody to coupler face.
  20. chinapig

    chinapig TrainBoard Member


    I'm attempting to close couple my F7s but the 923090 parts are still not available. Are there any alternatives to this part.

    Cheers, Ted

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