McHenry Couplers- A Modelers Plea.

Inkaneer Sep 1, 2008

  1. NikkiB

    NikkiB TrainBoard Member

    MT low profile wheels track poorly through switches. I have not found this to be the case with other low profile wheels.
  2. Leo Bicknell

    Leo Bicknell TrainBoard Member

    You made me do it. :tb-biggrin:

    I got out my verner calipers (+- 1/10,000) and measured some wheels. To get these results I found where the flange and wheel diameters were just snug, subtract one from the other and divide by two to get the "average" flange size.... Note, all these wheels have a slightly tapered wheel tread, so I tried to measure the middle of the wheel tread.

    MT Pizza Cutters:
    Flange Diameter: 0.275 (44.0 scale inches)
    Wheel Tread Diameter: 0.205 (32.8 scale inches)
    Flange Size: 0.035 (5.6 scale inches)

    MT Low Profile:
    Flange Diameter: 0.2427 (38.8 scale inches)
    Wheel Tread Diameter 0.2045 (32.7 scale inches)
    Flange Size: 0.0191 (3.0 scale inches)

    Atlas (off a box car from earlier this year):
    Flange Diameter: 0.2534 (40.5 scale inches)
    Wheel Tread Diameter: 0.2045 (32.7 scale inches)
    Flange Size: 0.0244 (3.9 scale inches)

    Athearn (off one of the box cars from my most recent video, w/mchenry in the jewel box):
    Flange Diameter: 0.242 (38.7 scale inches)
    Wheel Tread Diameter: 0.2036 (32.6 scale inches)
    Flange Size: 0.0192 (3.1 scale inches)

    For reference, the NMRA specifications are at NMRA - S-4.2 Wheels, Standard Scale and say....

    Max Flange Depth 0.022

    There is also a fine scale standard, at

    Max Flange Depth 0.017

    If you wonder how this relates, the NMRA standard for flange clearance is here: NMRA - S-3.2 Standard Scale Trackwork

    Minimum Flange Clearance 0.022

    I've been told (but can't verify) Atlas Code 55 allows about 0.025 of clearance on the switches (which are a bit tigher than the flex track).

    For the record, I advocate they all make a 0.021-0.022 flange size their "standard" wheels. These meet the NMRA standards, have a good sized flange.

    But, these dimensions clearly show MT is on both ends of the spectrum. The largest flange available, and the smallest flange available. Are your Atlas box cars falling off the track with .024 flanges? If not, then the pizza cutters are totally unnecessary.

    Oh, and obviously these are injection molded plastic wheels, I suspect +- 1/1,000 is totally expected wheel to wheel, perhaps more.
  3. BarstowRick

    BarstowRick TrainBoard Supporter

    Let it be so!

    Hey Tony,

    Let it be so.

    Darn it Tony! Do you always have to be right? I just took apart one of the couplers you mentioned. This is getting expensive... Bingo. Doesn't hurt to be edumacated on a subject before one jumps in to a discussion. Now, I know this can't be true of all of MTL's. Still you illustrated the most popular ones used. As I said earlier, "It takes a spring to make a slinky". I think I said that...LOL. Anyway! My apologies for not believing you in the first place. On the other hand I needed to see this. I can only hope others needed to see it as well. Thanks for the illustration.

    Now what are we going to argue about...I mean discuss? Grin!

    Edited add on:

    You know I can't let this go without a little fight...grin! The only point left to make is that although MTL's are not prototypically correct as in a precise copy of the prototype. The same idea has been applied to reproduce the prototypical cushion and what rails call "Slack". Unfortunately, the action appears to be over exaggerated thus the new acronym "Slinky". I still prefer to call it "Slack" and believe that as the engineer you can control it... as much as the real rails do and can. Not much! And, for the biggest part of this discussion the slack on the real rails is being ignored.

    I can't say with certainty that my equipment is all of a solid coupler post. However, I did open a few of the older ones and found the solid post. Just not sure why? As Tony takes a deep pocket to accommodate the spring arrangement. After looking at the PDF, MTL file as provided by Leo, (it's coming up in the next thread) it appears that all of MTL's coupler pockets are of the same basic spring design with one exception, the T Shanks.

    With regard to my layout, it has a flat area and try as I might, I did not reproduce the dreaded "Slinky" effect. I would think the train would stretch out considerably as it makes the start up the grade and bunch up considerably as it goes down hill. Other then normal slack nothing seems exaggerated. I will be looking for the "Slink" on my sojourn down to San Diego. Maybe I can get Tony Burzio to show me this on their N scale club layout.

    Tony H., good to hear from you and to hear your side of the story. Glad to be the one to engage you in a most interesting discussion.

    Have fun!
    Last edited by a moderator: Sep 7, 2008
  4. Leo Bicknell

    Leo Bicknell TrainBoard Member


    You can see from the diagrams if the spring is an in front of, or behind spring.
  5. jagged ben

    jagged ben TrainBoard Member

    Thanks Leo for the numbers...which more or less confirm what you were saying, which has always been my perception as well.

    FVM wheels would be very similar to MT Lo-pros in flange size. Probably true for Atlas and IM metal wheels, too.

    Kato wheels seem to have mid range flanges like Atlas. A lot of old "lo-pros" such as the typical Roundhouse wheels also seemed to be mid-range.

    So Atlas plastic wheels aren't quite NMRA compliant either!! Hah! Well, at least they are compliant with their own track. I agree with those that think MT has gone the wrong route by sticking with the pizza cutters. As long as Matt keeps the FVM wheels coming (even occasionally), they've lost the replacement market as far as this customer goes.

    With Atlas bringing on their code 65 snap-track product, I think we're on the way to proving that pizza cutters and code 80 rail are not necessary to keep trains running. Athearn seems to tell which way the wind is blowing, but MT?

    I have never considered flange depth (in these ranges) to be a significant factor in derailments. I have always blamed derailments on track, gauge, or improper riding. So I've always bought the wheels that looked best...MT lo-pros or FVM.

    That said, it helps to have as few different flange types as possible in your fleet when it comes to tweaking track.
  6. NikkiB

    NikkiB TrainBoard Member

    Hey, Leo, this is helpful!!! Thanks!!! I have never seen this before, but certainly find it helpful.

    I wish their website was easier to navigate. :-(
  7. NikkiB

    NikkiB TrainBoard Member

    True. Good point... Maybe Joe can illuminate the source of the decision making process.

    My position in the statement was based on the presumption that the decision to move away from the lo-pro and back to the pizza cutters was based on user complaints. Maybe this presumption was incorrect.

    Personally I haven't had a problem with them, but that's because I replace MT wheels with metal wheels.

    US based cars are easy to change, european based cars are a difficult subject. Metal wheels are very expensive and couplers very often require extensive modification.

    Still, I would like to be able to run MT cars out of the box on the variable track that I have. This isn't always possible.

    As discussion shows on another thread, ME/MT clearances are close, however MT wheels out of the box are certainly NOT compatable with Atlas Code 55.

    Want to test yourself? Take a brand new, current issue MT the C&O Cameo cars...put one on a piece of rigid Atlas Code 55 rail...incline the rail. NO MOTION. Take the same car and put it on a piece of Atlas Code 80 rail...incline the rail. The car rides off the rail. QED.
    Last edited by a moderator: Sep 10, 2008
  8. Leo Bicknell

    Leo Bicknell TrainBoard Member

    I don't think it's impossible, since they went to a finer profile than everyone else.... There may have been some legitimate complaints about tracking ability; but I think that should have been expected. Going from one end of the spectrum to another was a bold, and perhaps foolish step.

    Here's my theory on how it went down....

    MT was sitting around talking about the flange issue, and they knew they were about to fall behind. They wanted to step forward and impress the fine scale modeler, so they talked to people who really wanted smaller wheels and the factories. They decided the "lo-pro" was the finest size that could be reliably produced using the methods the factories could use at the price point they wanted.

    So they made them, and they were very well received by the people they built them for, people who wanted wheels on the "closer to the prototype" end of the spectrum.

    Then, a few years later those MT guys were sitting around going, "you know, we spent $big number on the tooling, but only 3% of N Scalers have bought the replacement wheels", and someone else chimed in "we should just make them standard, those pizza cutters are out of date anyway. Everyone loves them, we've had no complaints."

    So they did, and no doubt some people did complain. Was the it 2% who always complain just because it's change? Was it the 5% with really, truly bad track? Was it 30% of the modelers because they really don't work? Was it the collectors for some reason I will never understand? I don't know.....but back to the MT war room....

    "People are complaining. What do we do?"

    "Ride it out, it's the 2%."

    "We can't, it's the 30%, we must go to a higher flange."

    "We still haven't paid off $big tooling cost for the low pro, no way I'm investing $big again on some other size."

    "We can make more of the pizza cutters, right?"

    "Yep, tooling is paid for on those."

    "I guess that is our only option. Let's do that."

    This post is only a guess on my part, I have no inside information. It sounds like a good theory to me though.

  9. NikkiB

    NikkiB TrainBoard Member

    EXACTLY. Leo, I think you hit it on the head.

    You know what? This whole thing with flanges and rail clearance has been discussed very hotly over the last two or three months.

    Most of the items discussed have come down to opinion or interpretation of fact. I think that you should think about making a "Reality Reduced" piece about track options and the plusses and minuses of each combination.

    Certainly, allot of the items discussed recently have struck a chord in N-scalers. This would be an opportunity to provide a visual reference for modelers to "make their own decision".

    Just my 2 cents....

    John Baugher
  10. Leo Bicknell

    Leo Bicknell TrainBoard Member

    I actually have plans to do that, but it is much, much harder than it sounds.

    To properly show things on TV I need extreme close up shots. I need to be able to show rail profile, and wheel shape. I also need some animations.

    It's absolutely a segment I want to make, and have wanted to make before I started the show. There is not enough good information out there for modelers. The difficulties mean I'm not sure when it will happen though. :tb-sad:
  11. brakie

    brakie TrainBoard Member

    Leo,LP wheels as a standard will only come with demand-just like body mounted couplers.
    Untill that day arrives we will continue to see pizza(in my best Homer Simpson voice mmm pizza) cutter wheels and truck mounted couplers.

    Will that day come? More then likely.

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