Model Railroading > Question about curve radius - N scale

I'm already starting to design an N scale layout for a house my wife an I are considering. However, since we're looking at your typical starter home, there isn't a whole lot of basement/attic/garage space for a layout. So, the spare bedroom that will become the computer room/train room will have to suffice. Ideally, I'm looking at building a bookshelf layout in an L shape around two walls of the room. I'm definitely staying with N scale, but instead of a point to point layout, I'm actually wanting to use a dogbone design if possible.

The trouble you run into, however, is the obvious space requirements for the 180 turn. The "shelf" space would be just over 2 feet, so around a 12" radius curve would be needed on each end. Would this be too tight for a train of decent length, or cars of scale length (Amtrak coaches, autoracks, etc)? I know that curve radius has a direct effect on the speed and length of the train/cars you can run, but before I continue on design, I'd like to know what limitations I would need to really face.

The alternative is the old "door" layout, but I think the bookshelf would still allow me to do more in a tighter space.

Thanks!

-Eric Shock

Of course, the wider the radius the better....from both visual and operational standpoints. That said, a great deal of available N scale equipment is designed to operate on 9 3/4" radius curves...even a lot of the longer stuff. However, IMHO, a lot of equipment will look pretty rediculous on curves that tight, especially the longer locomotives and cars. I would try to go as wide as possible on the radii. I have about 21" minimum mainline radii on my N scale layout which is probably wider than a lot of people have, but I wouldn't want my curves to be much tighter (although I've seen a lot of great looking layouts that I'm certain had tighter radii than 21"). Another trick that can reduce that large-scale, toy-like look if you must use tighter radii is the addition of tangents at each end of a curve. This allows for a more gradual transition into the tightest point of the curve and reduces the initial exagerated overhang you will get if you go straight into a tight radius. If all else fails and you're stuck with seriously tight curves that don't look right, you can conceal the tight curves in tunnels. Just watch out for placing tunnel portals along the curve as you will likely run into clearance problems with the overhang of longer equip. Hope this helps!

T-fan

It does... especially the reassurance that most N scale stuff can run on curves as low as 9". However, the width of my proposed layout is pretty much determining the radius of what I can do. At the 90" curve, I'm looking at going with the 21" radius curve - perhaps double-tracked.

This layout is still just a pipe-dream at this point (we are still house hunting, and I'm basing designs off what we've looked at thus far), but it gives my mind a chance to dream realistically. :)

-Eric Shock

It depends on what era you model, for me I model the late 1950's on the Nickel Plate (short cars, and some what short locomotives). The space is two feet by four for my little empire. My only big gripe with my layout is that it has a 9 3/4 curve trackage on one full side and the siding, it's a real pain since my life like Berkshires can barely pull on these tight curves, but when they are on a 11 or 13 inch radius they do just fine. So my advice is to stay away from 9 3/4 curves as much as possible, they are a royal pain in the butt for operations.

tehachapifan Wrote:
-------------------------------------------------------
> "......... look if you must use tighter radii is the
> addition of tangents at each end of a curve. This
> allows for a more gradual transition into the
> tightest point of the curve and reduces the
> initial exagerated overhang you will get if you go
> straight into a tight radius......."
>
> T-fan


"Tangents" are straight sections. I think that you mean "spiral easments" at each end of the curve. John Armstrong explained how to set these up in his book "Track Planning for Realistic Operation" They will add a little to the overall width required for the shelf. A 180° 15" radius curve with 1/2" offsets on the easments will have an overall width off 31" between track centers. This will mean at least a 35"-36" shelf width at the return loops. With any thing less than an 18" radius I would try to stick with mostly 40'-60' cars.

Bob