The four feet make 48", so you can get that 22" radius half circle in there with about 1.5" to spare on each end of that turnback curve. Except, it's pretty close to those edges of the table where they start making that figure 8 again. You might be better off with 21" radius or build some kind of a barrier at the table edge to prevent catastrophic falls.
You can have a figure eight provided the crossing in the middle doesn't cause phase/polarity conflicts. If the crossing you use there has isolated routes, you should be fine.
If you intend to run an outer oval with a separate figure 8 inside of the oval, you will probably have enough clearance with a roughly 3" separation, but I won't be putting money on it. This is something you'll need to mock up first with temporary track and run cars and an engine past each other along the nested curves.
Welcome to the forums.
Radius referrs to the half the distance across the circle that would be made with that track. The measurement is made from center to center of the track, thus 22" radius track makes a 44" circle, but you use most of your 4' due to the width of the track.
I have a 4x6 layout and installed a plexiglas barrier around the outside to keep trains from taking a dive to the floor.
I have an Atlas Custom-Line Layouts (2nd Edition) book that shows the smallest fugure 8 layout using 18"r track, as needing a 42"x78" space. Your 22"r track would not make a circle large eough to fit the 18" loop inside.
Sorry to be the bearer of bad tidings, but....
Good luck,
Richard
cowman Sorry to be the bearer of bad tidings, but.... Good luck, Richard
And I'm sorry to be the bearer of bad news as well.
Robert
LINK to SNSR Blog
Edit: Oops, OP said 4x7 not 4x8
36 inch diameter inside a 44 inch diameter inside a 4 x 8 box.
And a folded dogbone which is a lot like my first layout. One track folded to look like a figure 8 in an oval.
- Douglas
It fits ...
... but most likely something more interesting and engaging would also work in the same overall space once you include aisles.
I included 3" track-center-to-track-center spacing between the 18" radius and 22" radius curves.
Good luck with your layout.
Byron
Layout Design GalleryLayout Design Special Interest Group
cuyama It fits ... ... but most likely something more interesting and engaging would also work in the same overall space once you include aisles. I included 3" track-center-to-track-center spacing between the 18" radius and 22" radius curves. Good luck with your layout. Byron
Yeah. I figured on a 30-degree crossing and 2-1/2" (or even 2") clearance at the ends of the loops. That would leave about 1-3/4" to 2-3/8" clearance to the ends of the 7-foot table; about the same as the clearance to the sides.
It works . . . but I agree, there are many other options.
Huh, it also just works with a 30° crossing, which brings the end curves in a bit from the edge.
Unless you're running nothing but trolleys or 40' boxcars pulled by 0-6-0s, then an HO scale layout should have a minimum curve radius of no smaller than 30", otherwise your layout is no good. Take a look at all the HO scale layouts featured in Model Railroader -- their minimum radius is always over 30". I learned this the hard way years ago, now I model in N scale, where you can run anything on 18" radius curves.
Metro Red Line Unless you're running nothing but trolleys or 40' boxcars pulled by 0-6-0s, then an HO scale layout should have a minimum curve radius of no smaller than 30", otherwise your layout is no good...
Unless you're running nothing but trolleys or 40' boxcars pulled by 0-6-0s, then an HO scale layout should have a minimum curve radius of no smaller than 30", otherwise your layout is no good...
I don't think it would be possible for me to disagree more strongly without coming across as a boor. But disagree I do.
While it could be argued that in recent years more newer and seasoned modelers are finding ways to enlarge their radii (when possible), the fact remains that many in the hobby, both new and old, still rely on 18" radius curves, and some dip even less. I bet you'll get reponses here from those who do exactly that.
There are reasons to go wide, but one needn't put away one's tools and rolling stock and take up knitting just because 18" radius curves are tight and restrict one's choices of rolling stock.
Metro Red LineUnless you're running nothing but trolleys or 40' boxcars pulled by 0-6-0s, then an HO scale layout should have a minimum curve radius of no smaller than 30", otherwise your layout is no good. Take a look at all the HO scale layouts featured in Model Railroader
Actually, an amazing amount of equipment will run on 18" curves in HO and most will run on 22" or 24" curves. Many modelers avoid these curves because of the overhang. And it's true that the largest cars and locomotives run better on 30". But many fine layouts have appeared in MR over the years using 18" or 22"/24" curves (22" fits 4x8 tables and is available in sectional track). Most of the annual project railroads in MR are around 4x8 and use 18" radii as their minimum.
40' cars and small engines can be run on 15" curves (available in sectional track).
While it's true for all layouts, small layouts especially need good track work to operate well. Tight curves and poor trackwork is almost always a disaster. Checking cars and locomotives NMRA gauges is also helpful.
Most of my early layouts used 18" curves very successfully.
Paul
Metro Red Linean HO scale layout should have a minimum curve radius of no smaller than 30" otherwise your layout is no good
There are literally thousands of counter-examples over the years.
Metro Red LineTake a look at all the HO scale layouts featured in Model Railroader -- their minimum radius is always over 30".
Demonstrably false with 30 seconds of research. There were HO layouts with minimum radii below 30" in the April, March, February, and January 2018 issues -- and those were just the magazines within arm's reach.