I use mostly Micro-Trains N-scale couplers, but some of my locomotives come with MT coupler clones (such as Atlas and Intermountain). I recently encountered an issue with the Intermountain couplers, which may be of interest to some on these boards. Note the image below, which shows an IM F7 on the left and a MT freight car on the right. Their couplers are over an uncoupling magnet, are in the open position, and the F7 has just begun to pull away. Note the minimal clearance between the tips of the hooked portion of the couplers. This is apparently due to a difference in the shape of the IM couplers, such that the hooked portion is very slightly wider (the vertical dimension in the image) than that on the standard MTs. On my layout, this has resulted in unreliable uncoupling, especially when both couplers are IMs. (A pair of MT couplers always uncouples reliably). On the occasions when this occurs, it appears that the minimal clearance has resulted in the tips of the couplers catching when separation is attempted. This issue appears to be entirely due to the wider IM hook, and not due to any friction in the mechanisms (flash, etc.). I am experimenting with solutions, the first of which will be to try to shave a tiny amount from the outside of the tip of the IM coupler, thus giving more clearance. If this doesn’t work reliably, I will have to replace all my IM couplers with MTs, which would be a shame. BTW, I realize that the MT coupler in the image is a 1980s model. However the latest MTs, although they have reinforcement added on the outside of the “hook”, have the same narrow hook, thus giving the same adequate clearance. You can see this by taking 2 unmounted couplers, and holding them together in a coupled position, viewed under a magnifier. A coupler with a normal MT-width hook, when coupled to a coupler with a wider hook, will show a slight gap to the outside of the tip of its hook, thus illustrating the difference in width. We are talking about a very small dimensional difference here. (EDIT: It has been determined in the course of this thread that the couplers referred to above as "IM" are in fact Micro Trains RDA (Reverse Draft Angle) 1015 couplers. The problem described above is thus present in MT RDA couplers, but not the older MT coupler models, which are still (so far) being produced. See the rest of this thread for possible solutions.)
Thanks for this post. Have recently replaced all of the "M-T?" trucks on all of the IM cars. Didn't know if any others have had problems with the IM units until now.
I was not aware the couplers IM uses were not Micro-Trains. This is from IM's own website page on F7's. "*All asterisked items are equipped with the appropriate Micro-Trains® body mounted couplers." Are MT making a different coupler for IM? I can't imagine MT allowing IM to call their couplers MT's if they are not.
I thought IM was using standard MTs too, until I examined them side-by-side under magnification. The IM couplers on my SP F7s don't have any MT markings or numbers on them, however, and the hook is a little wider. I just bought some new 1021s from an on-line retailer, and they were the same width as my old ones, and less wide than the IM MT-like couplers on the F7s. To confirm this for yourself, remove 2 of the IM F7 MT-like coupler boxes, and try to push them together; note the resistance. This resistance is indicative of inadequate clearance, which will make reliable uncoupling difficult.
Here's a picture of a recently purchased Micro Trains 1021 coupler "hook" with an Intermountain F7 coupler hanging from it. Note the greater width of the IM hook, as evidenced by the gap visible to the left of the MT coupler hook. As mentioned above, this greater width ruins the ability of the IM coupler to uncouple over magnets. So the question is, who actually makes this coupler for IM?
Mark, Try comparing the IM coupler to a 1015. 1015's are what IM is using, they are not making their own coupler. 1015's and 1016's have the RDA coupler faces and is the new standard body mount coupler that works with almost all current diesels (except Kato). The 1021's and other 1020 series T-shank couplers are the older design and do not have the updated RDA knuckle on them. The RDA coupler was designed to eliminate unintended uncoupling in long trains. I had thought that most of the common couplers had been updated by now but looking at MT's product reference sheet, only the 1015 / 1016 coupler has the RDA face on them. http://www.micro-trains.com/Coupler diagrams.pdf
Larry, Interesting information. However, if you are correct that the IM F7 MT-like couplers (with overly wide hooks) are actually MT RDA couplers, then I sure hope MT intends to retain the old design as well. As I mention above, the couplers on my (otherwise excellent) Intermountain F7s ***don't*** reliably uncouple over magnets. I think I will order a pack of the 1015s, to be compared with the IMs.
This reflects what I've said on one of the other coupler threads going at the moment, that MTL's RDA couplers cater to the long train crowd at the expense of the couplers qualities that make it useful to those who like switching and operating, ie; easy coupling and uncoupling.
Here's a link for RDA (reverse draft angle): http://home.earthlink.net/~bhender730/sitebuildercontent/sitebuilderfiles/rda_mt.jpg It doesn't say anything about changing the width of the coupler hook. It just notches tip of the hook, so it doesn't tend to slip up and off when coupled. I will swing by my LHS tomorrow and pick up a package of 1015s to compare with the IM couplers, and report on the result. Stay tuned.
Tony, I think you have just explained the problem I've been having for the past two years - trying to get MT couplers to work reliably under magnetic uncoupling conditions on a small switching layout. I've been changing all my stock to body mounted 1015 couplers and I have been finding that I can't get reliable uncoupling. I have seen that the problem appears to be the coupling knuckle not moving sufficiently to provide enough clearance for the knuckles to part. I might have to investigate other MT couplers to see if they work more reliably. The only problem is that they will cost more since I can't get them in cheaper bulk kit packs. :munhappy: Jim.
Oh yes, the RDA Coupler....... When I worked at Kato I was involved in the magnetic version of the Kato knuckle coupler. I had great hopes for it as the preproduction samples I received worked great with the M-T and Accumate couplers we tested. Unfortunately, none of the samples was the "RDA" version where M-T reversed the draft angles on the tooling, thus fattening up the knuckle. I made that error in not knowing that the RDA was fatter than the old M-Ts.... but the factory screwed up in setting the coupler centerline mounting too low (really wrong on the RDCs!!). They refused to own up to the error even though I pointed out their own drawings dimensioned the error into the tooling. Their solution was to change the mounting height of every frame/sill on subsequent products instead of correcting the coupler tooling. Oh well!!!! Apparently there is enough slop in the M-T couplers that they haven't had to change the 20XX couplers for newer Kato locomotives (or nobody has noticed that the couplers are not at the correct height because of the change in mounting heights). Charlie Vlk
We really do need some real coupler standards in N scale. It used to be all Rapidos that worked with one another or all MTs that worked with one another, now everyone's got their own couplers that sometimes don't work well together and even individual manufacturers are changing designs so their own couplers don't even work together.
FYI, I did manage to pick up a pack of Micro Trains (MT) 1015/1016 couplers today. I compared them under magnification to the so-called Intermountain (IM) couplers, and they appear to be identical. So Tony Hines is correct. My conclusion is that while the MT RDA couplers (referred to earlier by me as "IM") may be good for running long trains, they are not good for automatic (magnetic) uncoupling. I therefore hope that the fact that MT restricted the RDA changes to 4 new couplers was intentional, and that MT will continue to sell their previous coupler models without the RDA changes. So I need to figure out a fix for my F7s. My next step will be to see if I can cut away the extra material at the side of the 1015 hook / knuckle, to produce adequate clearance. If that doesn't work, then I guess I will have to replace them with an older MT coupler model, as the coupler moving parts don't seem to be interchangeable (the pivot point on the RDA coupler halves is in the rear). Mark
I've just checked the MT web site and I find that the body mount couplers I would want to use on my freight stock are all RDA - i.e. 1015, 1016, 1023, 1025. So I don't have much option for an alternate non-RDA version. I'll maybe have to look at their Z scale range unless someone tells me that they have applied RDA on them as well.:tb-biggrin: Jim.
Crap... I see what you're saying, in that the Micro Trains coupler order page (http://www.micro-trains.com/pl-NCouplers.php) lists RDA for additional coupler types, in contradiction to their spec sheet linked earlier in this thread... I think I will try to contact them directly, to see if they have a comment on this. MH
I spoke with Joe at MT about this issue, which he wasn't aware of. I also emailed him details of my experiments. In the meantime, I have had some success with the following procedure: 1) Ensure that the RDA couplers are burnished with graphite on the working surfaces (internal and external) per MT's instructions. Intermountain assembled their own, and may not have done this. 1015s which I assembled myself operated more smoothly. 2) More importantly, narrow and round off the flat tip of the MT RDA coupler knuckles, and burnish. (Try not to remove the reverse angle when doing this). The portion to be removed is marked in orange in the image below. The coupler assembly is best removed from the Locomotive when you are doing this. Mark
Mark, Another thing I was trying out to improve the situation was limiting the movement of the non-knuckle part of the coupler by attaching a small piece of brass angle to the front of the coupler box The angle limits the movement of the non-knuckle part only and allows the opening to be a bit larger. This was just experimental but seemed to do the job. The angle was glued on with cyano - carefully. :tb-biggrin: Jim
Guys, this is a great thread and very useful, and I appreciate the work and time Mark and others put into it. But it also illustrates a fundamental problem of modeling in N scale: instead of being able to focus on creative modeling activities like kitbashing that new loco, building structures or scenery or whatever it is we like to do, we have to spend precious modeling time dicking around with couplers for god's sake. In 2011! We NEED some standardization... End of rant, Otto
Oh we've definitely noticed. Search this forum for '2003 coupler'. To convert the latest Kato locos at a good coupler height you now need to put 1015 shanks in 2004 boxes. Thanks for your comments on this Charlie.
What we need is consistency. I tried Accumates and McHenry's and have standardized on MT's I find I have less problems when things are consistant than when they are not. I am now standardizing my rolling stock so they conform to the NMRA standards for weight.
