list of 6 Axle diesel on 18" radius

Discussion in 'HO Scale Model Trains' started by alexander, Oct 27, 2006.

  1. alexander

    alexander Member


    i thought we should make a list of locos that will handle 18 inch curves

    lets start with my

    ATLAS SD24

    now, if you know it will handle the 18" curves, tell us

    maybe an admin might like to sticky it, so everyone can find it

  2. MilesWestern

    MilesWestern Active Member

    Most locomotives are designed to handle 18" radius curves, but none, with the exeption of a few industrial switchers, look good doing so. The Athearn Big Boy was designed to handle those curves, even though it'd NEVER happen in real life. The list for locomotives than CANNOT would be a shorter one.

    Don't mean to burst your bubble if I did! :cry: :oops:
  3. Russ Bellinis

    Russ Bellinis Active Member

    I had an Athearn sd45 that would go around a 15 inch radius, but the coupler hung so far off the side of the tracks that a box car hooked to it went up on the outside wheels ( I was going to say 2 wheels, but it was actually 4 wheels) around the corner and then dropped back down on all 8 wheels! The point is that even if a locomotive will go around a particular radius does not mean it can haul anything else around that radius.
  4. alexander

    alexander Member

    Yeah i know

    what i meant was a list for beginners (like me) to refer to. My SD24 will go around the 18" curves, but it wont couple (it pulls them ok tho) this is using Horn Hooks tho
  5. alexander

    alexander Member

    'nother thing, forgot to mention, my SD24 doesnt look too bad (it doesnt look great either tho) around this curve
  6. AndyWS

    AndyWS Member

    Athearn F-M Trainmaster handles 'em okay, Athearn SD40-2, P2K E6A, and P1K Erie-Builts do not, all make squealing or grinding noises as if the truck mechanism is being strained.
  7. LongIslandTom

    LongIslandTom Member

    Report on the 6-axle locos that I do own:

    Athearn blue-box SD40-2 - will have trouble staying on the rails going around 18" radius snap track, but will negotiate superelevated flex-track 18" curves as long as there are no kinks in the track joints.

    Athearn blue-box SD40T-2 - This unit is substantially longer than the plain SD40-2, and it won't go around 18" radius of ANY kind. There simply isn't enough truck swivel, and wheels will simply pop off the tracks.

    Athearn blue-box FP45 - Same problem as the SD40T-2. Very long body, insufficient truck swivel. Won't go around 18" radius of ANY kind.

    Athearn blue-box F45 - This unit is actually a bit shorter than an SD40-2, and it will go around 18"-radius snap track without derailing, but just.

    I think the rule of thumb is that if a particular 6-axle loco is shorter than an SD40-2, it probably will go around 18" curves. Any longer than that, probably not a good idea.
  8. wickman

    wickman Member

    Can we do this for steam engines too?:wave: we don't want them feeling left out.
  9. pgandw

    pgandw Active Member

    My rule of thumb for steam on 18" radius curves is that if it won't fit on a 10" turntable, it's too big, and will look horrible on the curves. Also, engine to tender separation will have to be huge.

    That said, almost all HO steam models (except brass) with 8 drivers or less (x-8-x), will go around 18" radius curves. With 10 drivers (2-10-0, 2-10-2), only the smaller Decapods are going to make it.

    Almost all HO non-brass articulateds will go around 18" radius curves, but will look horrible doing so.

    Again, my rule is nothing bigger than a 2-8-0 on 18" radius. Any modern (post 1910) steam power with trailing trucks (4-6-2, 2-8-2, and up) should have bigger curves. The smaller engines look much better with the short trains of 40ft freight cars that are most appropriate for 18" curves.

    my thoughts, your choices
  10. LongIslandTom

    LongIslandTom Member

    My report on the steam engines I own or worked with, as per Wickman's wishes: :D

    Thomas the Tank Engine - I bought this as a birthday present for my little 5-yr. old nephew. Will work on 18" radius track no problems at all whatsoever. :thumb: sign1

    MDC Roundhouse Old-Time 2-8-0 Consolidation - I just purchased this one a few days ago to be given as a gift for my brother-in-law this Christmas. It has slop on the drivers wheels and will negotiate 18"-radius track no problems. The LED headlight on this puppy is BRIGHT...

    Broadway Limited Imports 4-6-4 J1e NYC Hudson with Quantum sound and DCC: No problems going around 18" radius curves whatsoever. This is the first steam engine I've ever purchased and I love it to death, considering that it only cost me $129.
  11. Triplex

    Triplex Active Member

    In real life, SD40s and SD45s are about 3' shorter than SD40-2s and SD45-2s. F45s are about the same length as the pre-Dash-2 SDs.
  12. LongIslandTom

    LongIslandTom Member

    Yep. The F45 works out to be a little over a third of an inch shorter (10.5mm) than the SD40-2 in HO (wheelbase-wise anyway).. So I think the pre-Dash-2 engines like the Athearn SD40, SD38, Kato SD45 should be able to go around 18" track. :thumb:

    Pilot overhang/coupling issues still apply though of course..
  13. Triplex

    Triplex Active Member

    And, of course, SD7s, SD9s, SD24s and SD35s are shorter than SD38s, SD40s and SD45s. However, there are no short 6-axle U-boats or Centuries. I think this is at least partly because they always put the dynamic brake section ahead of the prime mover instead of above it, while EMD only started doing that with the SD50.
  14. alexander

    alexander Member

    hey, if i was dead set on running somthing like a FP45 or a SD45T-2, how hard would it to be to gring some of the fuel tank away (i know what visual implications this will have, but oh well), to allow it the swivel to go around curves?

    oh yeah, i model a time when the Dash 2 was brand spanking new (anytime from 1970 to 1975 ('77 at latest))
  15. LongIslandTom

    LongIslandTom Member

    Heya Alexander,

    You can probably enlarge the opening in the frame where the trucks sit to allow them greater swivel (you don't have grind the tank, actually)..

    But then you will run into other issues-- The driveshaft and universal joints, when spinning, tends to exert forces on the truck to force it to straighten. Also, the trucks might bump into things on the shell like jacking pads that prevents them from swiveling any further. So those are a few potential issues you may have to deal with as well in addition to the frame clearance.

    Anyway, these days my 6-axle locos don't get much use... 4-axle power work much better on my tiny layout with its 18" curves, so these days the vast majority of the locos on my layout are 4-axlers... Geeps, GE Dash-8 B's, Geeps, U-boat-B's, Geeps, Alco S-series switchers, Geeps, EMD SWs, Geeps, Amtrak F40s and Gennies, and that's right, more Geeps. Did I mention Geeps? sign1
  16. Greg Elems

    Greg Elems Member

    IIRC my old Athearn SD9 did ok on the 18" curves. Looked funky but worked fine. As stated on an earlier post, wouldn't couple up but went through coupled ok.

  17. green_elite_cab

    green_elite_cab Keep It Moving!

    6 axle locmotives that o won and run on 18" track with no operational problems:

    Spectrum SD45
    Atlas U34CH
    Athearn SD75M, AC4400CW, C44-9W
    P2K SD7

    the Athearn ones do look a little ugly on 18 inch radius, but the others can run just fine on them and look right.
  18. green_elite_cab

    green_elite_cab Keep It Moving!

    the U36C is more or less the length of the SD45.
  19. alexander

    alexander Member

    some of these lists are interesting, like the b'mann sd45
  20. alexander

    alexander Member

    ahhhhhh, lot'a geeps. Actually (aside from a rarely used Tyco) i dont roster any geeps. i'll have to get a GP9. maybe a UP one, or a Great Northern. plus another SD24. thats all thats on my motive power roster for now

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