Just a little minimum radius info

DeaconKC Aug 16, 2022

  1. DeaconKC

    DeaconKC TrainBoard Member

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    If any of you are contemplating using a 249mm radius curve on your layout, I was testing some locomotives this AM to see which ones will work in the industrial area of a module I am building. Anyway, here is the info:
    1. Model Power 2-8-2 Mikado, will negotiate the turn, but NOT pull a car behind it, due to the tender mounted coupler.
    2. Kato 2-8-2 D51 [Japanese Mikado] Handled the turn and cars easily. [note; it still has the truck mounted Rapido coupler]
    3. Bachmann 2-8-0 Consolidation, handled the curve and cars easily
    4. Bachmann 4-4-0 American, didn't even notice the curve
    5. Atlas RS1, handled the curve and cars easily
    6. Lifelike GP18, Handled cars and curve smoothly
    7. Lifelike SW9, duh, zipped right through
    8. Backmann Docksider, made it easily
    Have a couple more locos en route, so will add to this when they arrive. I cannot imagine the new Bachmann 4-8-4 handling this, as my ancient one from the 80s would not run on these radius back then. And an ancient Minitrix 2-6-0 is on the way, so we will see on that one.
     
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  2. warnerj01

    warnerj01 TrainBoard Member

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    Thanks. My personal rule is 282mm or higher. I have a couple 249mm pieces, but I limit those to 15deg only to help align track pieces.
     
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  3. DeaconKC

    DeaconKC TrainBoard Member

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    Yup, I would too, except this track is going into the center of a T Trak set up for home and show use. I was sweating, worried I might have to go to 216 for the curve, but figured out how to avoid that!
     
  4. bremner

    bremner Staff Member

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    I actually got an Oriental Limited 2-8-0 to run on 180mm Unitram track...yes, it lifted the center drivers
     
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  5. brokemoto

    brokemoto TrainBoard Member

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    I can get the MP and a train around the 249 mm.
    The B-mann 2-8-0 is inconsistent. Some will do it. On some, the pilot derails.
    I can get an Atlas/Kato SD-7-SD-9 or a Kato RSC-2 around a 249 mm even with the body mounts as long as the car is no more than forty scale feet.

    I can get the diesel switchers and small steam locomotives through the UniTRAM curve pieces, but almost all of them stall on the diverging parts of the turnouts. Oddly enough, the only thing that I ever have managed to get through the diverging tracks with no stalling is the E-R Shark. The Kato NW-2s will go most of the time but stall enough that it is annoying with the result that I do not want to use them on those turnouts. The Kato RS-2 or Atlas RA-3 are similar. The MDC/Athearn 2-8-0 will go through the diverging with the same consistency as the Kato NW-2. The B-mann USRA 0-6-0, even with the SPECTRUM tender swap stalls too frequently. The B-mann GEs stall, but I blame that more on the small footprint. In pairs, they will clear. The B-mann "MDT" stalls or climbs.

    Using Sharks on that kind of trackage to switch businesses is not a prototypical use of those things. For this reason, I took the UniTRAM turnouts from my pike. The real reason that I was interested in the UniTRAM was the turnouts. I can make my own street trackage, but never have I been happy with the results of the turnouts that I have tried to convert to street trackage. A #4 street turnout would be something that I would buy.
     
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  6. DeaconKC

    DeaconKC TrainBoard Member

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    Thanks for the input on the Tram trackage. I have always loved the looks of the Sharks, you are evil, as now I want to find some! The Bachmann 4-8-4 is due in today, so I will find out what it will accept.
     
  7. CSX Robert

    CSX Robert TrainBoard Member

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    Some things to considering when looking at a locomotive's minimum radius.:
    1. You can often have a smaller minimum radius if you use an easement (with sectional track, a single piece of wider radius curve as a simulated easement will help).
    2. With body mounted couplers on the locomotive, you'll sometimes have better luck with body mounted couplers on the cars.
    3. Short shank vs. long shank coupler can make a difference.
     
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  8. DeaconKC

    DeaconKC TrainBoard Member

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    All good points to consider, I will retry the Model Power Mike with an easement curve!
     
  9. DeaconKC

    DeaconKC TrainBoard Member

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    Well the Bachmann GN 4-8-4 showed up today. It will negotiate the 249mm turn, but it was very fussy about what cars it would handle on that. Much happier on the 282mm track, but it did run on the 249!
    And tried out what @CSX Robert suggested on an easement using the 282 track into the 249. It allowed the MP 2-8-2 to negotiate the smaller radius, but still no joy on pulling a car behind it.
     
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  10. brokemoto

    brokemoto TrainBoard Member

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    Every once in a while, a pair will come up on FeePay, but the opening bid is usually high and there often is a sniping war at the end. Be careful of the first runs (Penn single stripe, NYCS Cigar Band, B&O 1959 schemes) as they have those B-mann gears that crack. There is debate on whether or not the NWSL wheelsets designed for the B-mann PLUS F-units will work.

    I have four B&O pairs; two with white gears, two with black. They show no signs of cracking. I did have some of the Penn single stripes and NYCS cigar bands (that I made into lightning stripes) show cracks. When I sold them on FeePay, I was surprised at the prices that they fetched as I did disclose the defect and set a low opening bid.

    I did manage to land a pair of Penn five stripes on the Swap Meet boards on this forum. Try a WANTED listing there.
     
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  11. Doug Gosha

    Doug Gosha TrainBoard Member

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    What are all these two hundred and some millimeters in human terms?

    Doug
     
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  12. mtntrainman

    mtntrainman TrainBoard Supporter

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    IKR ! Every time some types in MM I have to use my free 'convert' program to convert it into useful info for Americans. :whistle:

    https://joshmadison.com/convert-for-windows/
    .
     
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  13. brokemoto

    brokemoto TrainBoard Member

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    216 mm is seven and one half inches
    249 mm is just over nine and three quarters inches.
    282 mm is just over eleven inches.
    315 mm is just under twelve and one half inches.
    348 mm is just under thirteen and three quarter inches.
    381 mm is fifteen inches
    481 mm is just under nineteen inches.
    718 mm is just over twenty eight and one quarter inches.

    HO comparisons

    N scale seven and one half is just over thirteen and three quarter inches HO
    N scale nine and three quarter is just under eighteen inches HO
    N scale eleven inches is just over twenty inches HO.
    N scale twelve and one half inches is just under twenty three inches HO
    N scale thirteen and three quarter inches is twenty five and one quarter inches HO.
    N scale fifteen inches is just over twenty seven and one half HO.
    N scale nineteen inches is just under thirty five inches HO.
    N scale twenty eight and one quarter inches is just under fifty two inches HO.

    If you accept the standards of HO: Sharp: eighteen inches; Conventional twenty four inches; Broad thirty inches you can determine your needs in N from that.
     
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  14. DeaconKC

    DeaconKC TrainBoard Member

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    Sorry about that! I have been figuring stuff in Unitrack for T trak and didn't think of using Inch comparisons.
     
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  15. MK

    MK TrainBoard Member

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    Just divide millimeters by 25.4 to get inches.
     
  16. Shortround

    Shortround TrainBoard Member

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    My construction calculator does it just fine.
     
  17. warnerj01

    warnerj01 TrainBoard Member

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    Since Kato labels all of their track in MM, the only time I mention MM is when I'm referring to Kato track. It is just easier to refer to the specific track according to the labeled MM instead of referring and converting to both standards. It's way easier to refer to a 282mm curve track as 282mm instead of converting it back and forth to 11in.

    I still calculate my dimensions in inches. To ease my planning. I remember a few specific curve radiuses in In.

    282mm = roughly 11in
    381mm = roughly 15in
    481mm = roughly 19in
    781mm = roughly 28in

    For straights. I remember that a 248mm straight is just under 9.75" and divide from there.
     
  18. Inkaneer

    Inkaneer TrainBoard Member

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    Or multiply millimeters by .03937
     
  19. brokemoto

    brokemoto TrainBoard Member

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    You can Google "inches to mm". The first entry is something where you can enter either mm or inches in one box and the equivalent will show up in the other box.
     
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  20. Shortround

    Shortround TrainBoard Member

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    Or klick on the little windows symbol and then on calculator. It right there all the time.
     

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