HO radius recommendation

Discussion in 'HO Scale Model Trains' started by ls1gto, Oct 11, 2005.

  1. ls1gto

    ls1gto Member

    I'm in the ole "do I do N or HO" dilemma. I have a decent amount of HO rollingstock but I only have an 11' x 17' room to work with. I guess that sounds like a decent amount of room but I want to do a u-shaped point to point along the walls of the room with the door to the room being at the open end of the U. I just dont think I will have enough room for realistic radius's. I had originally planned to do this in N but as I said I have a decent amount of rollingstock in HO and more variety in what I want to do. What do you guys use as your radius guidelines?
  2. MasonJar

    MasonJar It's not rocket surgery

    11x17 is a huge space, even for HO.

    Having said that, minimum radius for bigger steam or diesels is 22", but some think that everything looks better on bigger curves (30"+). Smaller engines and rolling stock, as well as traction, can operate down to 18" or even 15".

    You should have plenty of room for sweeping curves in that space... What era/location/industries/etc are you thinking about doing?

  3. ls1gto

    ls1gto Member

    Well, as far as the era, it would be early 80's to present Norfolk Southern-Southern-NW. The location will be completely imaginary and will incoporate primarily coal, general freight and I'm sure more as I get further into the planning. Now, I'm going to ask a stupid question, when we say a 22" radius curve, does that mean the it is literally 22" from point to point. I know thats a really stupid question but I've just never really given it much thought. Thank you!
  4. kchronister

    kchronister Member

    22" radius means the radius along the centerline of the curve. i.e. if you imagine a quarter-of-a-pie-shaped slice the two straight parts would be 22" long and the curve would be the track (on a 22" radius curve). Another way to look at it is that a 22" radius curve takes 44" to turn fully around

    Modeling 80's to present I think you're fine on curves, even at 18". The things that require larger radius curves are generally big steam locomotives and long passenger cars - both notably lacking from 80's onward. Yes, some very large diesel locomotives (e.g. 'genesis' series UP) may have trouble on 18" radius, but very few in my experience.

    Without large passenger cars and steam locos, radius really becomes an aesthetic issue rather than operational. That is to say, 18" curves would almost never be found on a modern prototype mainline railroad (ignoring anomalies like logging railroads (out of era anyway), tourist railroads, and the like)
  5. Union Pacific

    Union Pacific Member

    I didn't see his he posted as I typed sorry!!

    the radius is the point from the center to the outer the circle what you are thinking of is the diameter. Bach mann e-z track is 18" radius or 36" circle (they also carry 22") MasonJar said it seems plenty enough to do HO. I do deisels and with unit trains and 6 axle locos, and 75' or more cars I would try and get a 22" of large if you wanted to you could always *bevel* the inside corners of the U to make room for a double main. Also how wide do you want this to be??? It sounds like if you really made it deep enough 3' or more you could puta small N scael in the background either a fictional line or just trsck to dive it the illusion of Depth :D ;) just my 2cents
  6. ls1gto

    ls1gto Member

    Thanks for the clarification on the radius. I think I could get a 24" radius in on the return points but I just wasn't sure that would be substantial enough for some fairly long trains and 3 axle units. (ie..SD80mac's etc...) What would the limit of a 24" radius be in terms of car length? I'm sure there are variables to that but a best guess would be great.
  7. Union Pacific

    Union Pacific Member

    I belive you can fit up too 80 or 85 feet cars on that you shouldn't have any ploblems running anything on 24". Laso one thing I do if they derail of squek cause the almost or do want to come off is sand down the little pocket (use yuor judgment) till it move more freely just what I do.

    Thanx, Ben
  8. Gary Pfeil

    Gary Pfeil Active Member

    Are you talking point to point or a U shaped layout with turnback curves at the ends? If you have 11' across and use 24" radius turnback curves, you'll have something like a 2 1/2' aisle. Of course, this can widen immediately beyond the center of the curves. And if you keep the shelves along the long wall about 2' deep, then you could also use a center stub ended peninsula about 1 1/2' wide, with aisles on either side about 2 3/4', This could be a coal mine or such. Although this would hinder you from following trains around the room that don't go down to the mines. Just thinking while typing!

  9. ls1gto

    ls1gto Member

    Thank you for pointing out my boo boo there. It is not a point to point but a turnback arrangement. You have nailed my problem right on the head. I can either offset the turnbacks to get a 28-30" radius and give up some length of mainline on one side or retain the 24" radius with side by side turnbacks and sacrifice the realistic appearance of the curve. Isn't a 24" radius just to small?
  10. MasonJar

    MasonJar It's not rocket surgery


    If you want continuous running, I would strongly recommend that you consider making a dunckunder or lift/gate section across the door. You will be giving up huge amounts of space (and creating some unreachable areas) if you incorporate "turnbacks" at each end of the "U".

    I have linked this layout many times, but I think it still is one of the best in the approximate size you are thinking of... Mike Hamer's Boston & Maine. I hope that will give you some ideas of what can be done.

  11. ls1gto

    ls1gto Member

    Thank you very much. I was trying to avoid that but I think your right that if I'm going to run HO this would be the best solution. The link you posted of the B&M is excellent and an inspiration. I truly appreciate your help and advice.
  12. MasonJar

    MasonJar It's not rocket surgery

    You are welcome. I have operated at Mike's a number of times and it is an excellent layout in a "relatively" small space. The well thought out track plan means you can have big trains in town without them looking out of place. His trackwork is flawless. And the duckunder has become another operating area, as you can stand outside the room in the doorway and work the staging like a yard.

    However, your duckunder does not have to be as complicated. A single line of track makes for an easier "duck". You could even make it removable. Search The Gauge for ideas - it has been discussed at length here ;)

  13. yellowlynn

    yellowlynn Member


    One thing I didn't find was where the door was. It could be on an 11' wall, or on a 17' wall. That would determine how I would set up.

  14. TrainClown

    TrainClown Member

    Put in a lift bridge and your trains can run right round the room with very lare turns indeed.

    TrainClown ;)
  15. ls1gto

    ls1gto Member

    Sorry I dont have a picture but the door will be in the dead center of the open part of the U and that is the 11' side(the open side of the U). The length of if would be the 17'.
  16. ls1gto

    ls1gto Member

    If I do the HO (which I'm leaning heavily twords) I may very well do something like that. Either a "duck-under" as previously suggested or
    some minimum scenary on a swing of some type. Thank you for your input!
  17. kchronister

    kchronister Member

    I'm facing the same dilemma on my layout. Do I have a "duck under" right inside the door to facilitate continuous running (which I want), or reconfigure the whole thing to point-to-point or loop-to-loop instead, which sucks up a vast amount of space to do... Or, if I have the 'duckunder' do I make it into a drop-bridge of some kind - which I've never done, but understand to be a great way to work on your cursing skills... Let me know where you go on this one, i'm curious to see your solution.

    As to gauge, I've modeled both N and HO and stick with HO. The reasons are basically intangible - something about N (just my personal feeling here, nobody freak out) just doesn't hit a critical mass of size. It doesn't satisfy me or feel "right." HO, for me, crosses that threshhold of being big enough to add a critical level of believability... Like I said, it's strictly a matter of opinion and intangible factors, but I'd definitely cast my vote in the "stick with HO" column.
  18. ls1gto

    ls1gto Member

    I didn't want the duck under simply because when freinds or family come over, I hate that they would have to squat under to get to the middle,buuuttt, they may just have to. Or, I could create a swing up section as previously suggested. I've pretty much decided that I'm going to go around the room. Its just to simple and efficient of an answer to ignore. I'll deal with the problems as they arise.(I'm gonna regret saying that very soon:D ).
    As far as the scale goes, I like both but I agree with you on the realism. However, N scale (for me) has its on special look and uniqueness that HO doesn't have. I think there both great and each has there advantages and dis-advantages. As you said, preference.
  19. tillsbury

    tillsbury Member

    The neatest trick I saw was the hinged 'gate', with a single track running over the top of it. It's easy to get in and out, and provided it's made with appropriate accuracy at each end it should just swing back into position. Clever wiring to stop trains accidentally falling off the edge (killing neighbouring track power when the door's open), and even (if you want to get clever) use block occupancy detectors to throw a relay instead of a signal, and lock the door when there's a train on or near the gate...

    Of course, in HO it's easier to line the track up too :)

  20. Gary Pfeil

    Gary Pfeil Active Member

    Those 24" radius turnback curves don't have to be visable. If you have the tracks, front and back, go into tunnels you won't have to deal with the visual, and that radius shouldn't present a problem with operation. If you build helix's on each end, you could have the front and rear tracks on different levels and have double the amount of scenes, and still have a walk in. Still just typing out loud.


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