Tightest HO Radius You'd Do?


Hey guys,

I'm planning a layout in my garage that is going to be loosely based on GN's route over Stevens Pass. I've started by modeling up the area between Scenic and Berne.

I've given myself 7' x 8' for this area, and I've been fiddling around with XTrkCad 3.1.4. I know from the design work I do for a living that you can get anything to fit, and work great on a computer, but real life if often a different issue. :D

I have a number of curves leading up to the old Cascade tunnel that are 2-1/2 feet in diameter, and some are 180 degree curves. I purchased 2 - 3' sections of track to help me visualize what I am drawing up, and it looks pretty tight to me.

I'm ok with tight curves on this part of the route, it's suppose to be an inferior route on the side of a cliff, but I don't want to pull cars off the track every time I go around a corner. What do you guys think??
Here is a picture of what I have been able to accomplish so far. The old route will connect to the new at Scenic and Berne, I just haven’t gotten that far yet.
The turn inside the tunnel is only a 12" radius. Geared steam might do okay maybe even some small steam, but your diesel might have a time of it. Layout your flex track in a 24" diameter circle and hook up a power pack and see how it does.
I plan to never again go below 22" radius, and that'd be for an industrial track, not a mainline. I'd prefer mains to be over 30" +. That said, the truth of HO railroading in small spaces is tight radius curves. I'd advise you to get more real estate or go to N scale. That's the hard truth. ;)

Here's something to also let you know about drawing layouts in XTC. When the track comes out red colored on the drawing, it indicates a substandard radius. In other words a radius that is not in the manufacturers parameter files.

With you wanting to do GN and Stevens Pass, which in all eras required GN's biggest power, and only the room you show, you really have three options, two of which G-man has said: 1. Go to N-scale, 2. Get more real estate, 3. Model one of the approaches to the Pass, with the Pass itself offline,ie not modeled, just suggested. Also, access to the middle of this drawing would be very limited.
Well it's an interesting plan, and I don't want to rain on your parade, however unless you'd be satisfied with truck mounted couplers and two axle diesels, or a lot of de-rails, I'd re-think about those tight radius curves. The scenery to go along with the tunnel and the grades would be interesting topic though :D

I won't go under 30 inch radius on my mainline, with maybe 24 inches in city and industrial track. Then again, I have a whole basement in which to play.

If you do Stevens Pass in the very eary 1900s, like prior to the first tunnel - the 2.7 mile one - under the pass opening, you might get close to what you want if you set your minimum radius to about 18" (three foot diameter). Then small steam and short trains were the norm, and will look good and operate reasonably well. You would also have the fun of modeling the original switchbacks, if those are of interest.
Your curves are way too small, per your drawing. You might get by with 18" radius, but 24" will be much better. Passenger cars won't do the 18" stuff very well, if at all.

You don't say your era, but if you're doing Transition, you might get by. I've run 4-8-2s and 2-8-2s on 18" curves, and the GP7/9 and F-Units will run on the 18" curves. They don't really look all that great, but they won't derail. And, the 40' boxcars will handle it OK.

Like others have said, that curve inside the tunnel is the biggest problem. Don't know really how to fix it, though, given the way that area is in real life. The only thing I can think of offhand is to move the West Portal (Tye) to about where that little black section of track is, and curve the tunnel there. That might be a good solution because that will allow you to move the start of the old grade farther up, and get you more radius.

Alternately, if you can live with a steeper grade, make the old tunnel overlap over the lower section. You won't be able to run doublestacks or autoracks, but a 40' boxcar might just fit.

Well that's what I was afraid of. I set up 2 of the curves with the 6 feet of flex, and yeah - it's way too tight I've thought about scaling down to N, but I think HO looks the best, and it's what I had as a kid. It also looks like the biggest selection is still in HO.

I'll have to look into getting more room, which I potentially have with a 3 car garage. I'm taking almost 1/2 of it right now with room to pass around the layout. It just depends on how bad I want this verses how big of a pain it is to accomodate the rest of the items in the garage, i.e. cars, sleds, lawnmower, etc. :rolleyes:

Thanks for the help guys, I was wondering how close I was to what could be accomplished, and I feel like I know that now.
THE ONLY place I'd ever put an 18" is in an industrial area, and at that I'd ONLY do install a maximum of TWO 18" radius sectional track pieces (or the Flextrack equal), before something wider... I had 22" radius turns on my first layout, and it bothered me because it was tight on my longer cars. I'm not dropping below 26"-28" when I build the next one, but my dad's RR is 22" with 18" in a few small places, running nothing longer then 60' and 4 axle units.
I'd like to run all 6 axle units except for a few road switchers that I'll run over the route. The time period will be a bit of a mix and match - YTD on the current main line, with the old cascade tunnel route as another option to get over the hill. I think that will keep it interesting - almost like a long siding.

I'll look into doubleing the size, and see what that gets me. If I still don't like that, then I'll likely prototype it without the old line, or do something totally different.
24" radius is the minimum I would use (HO scale). 6 axle locos will navigate tighter curves, but they don't look good doing so.

Instead of a table layout, what about going around the space and accessing it through the center. It will allow larger turning radii.

For example a 4 x 8 layout with 30 " of access around it takes up 9 x 13 feet of space. A 9 x 13 around the walls layout is a decent sized layout.
Well, like I said, your old line is holding pretty much to prototype fidelity. Which, given your space, that's not really going to work. You're going to either widen things, or reconfigure the old line by eliminating certain spots. The Windy Pt to Tye segment may have to be compressed.

I've thought about shelfing the layout around the garage. That would give me a TON of track, and the curves would be pretty smooth as stated, but that really takes up any storage space in the garage. I'm thinking of doing a combo of shelves, and tables. It's going to require more thinking........ :) Keep the ideas coming guys, you've been a big help so far.
You may want to think about putting the tunnels there; all you'd need is a 'tunnel' inside whatever storage space you're intruding upon. You'd have to plan for access in case of derailments (and there guaranteed to be there), but it's an option.

For single track, you're looking at losing one shelf (if the curve is there) for about a width of 3" or so (to cover the long cars). If the elevation is high enough, you can still store stuff underneath the roadbed.