Not sure of the accessability of your blobs. Can you reach in from three sides? Can you reach all trackwork relatively easily? 30" is about all most of us can reach, arm length and layout height are the controlling variables.
I have two corners I'm not sure I will be able to reach on the planned layout. When the benchwork is started I will do a double check. If needed I will leave a pop up behind the layout in each corner with a curved backdrop in front of each.
Good luck,
Richard
Thanks all. I had been planning on 18" radius for the inside track and 22" radius for the outside. My passenger train runs on 22". I run the trains at slower speeds.
That said, I did not consider that the need for a straight track to break up the S might require a larger space than 4' x 4', at least on the outside track. I also did not consider that the shape may present difficulties with longer trains on the S sections.
So, will it be impossible to do this with 4' x 4'? If so, then I will see if I have space for two 5' x 5' sections.
I've already beaten Tom's minimum by an inch. But I'd recommend reading on, because.......
I've got a shelf(ish) layout. One section has four straight parallel tracks. It is 11" wide. The tracks are at 2 1/2" centers, and the edge tracks are 1 3/4" in. There are track switches and crossovers involved.
It works nicely for me.
BUT.
The tracks are at 2 1/2" centers because:
(1) It's easier to put my paws in there to add, subtract, "correct" rolling stock.
(2) My curves are minimum 48" radius. And I felt I needed that extra 1/2" clearance. If I were running 24" curves, it would be a good bit more. Of course, the spacing of the curved tracks does not have to match the spacing of the straight ones. I chose to do so as it eased track design and I wanted that spacing in both places anyway.
The edge clearance is minimal because:
(1) At the rear, there is a wall.
(2) At the front, there is a notch that can receive a vertical clear acrylic "fall stopper". I've never installed any yet. Nor has any equipment fallen to the floor (yet). But, as they say, I've been warned.
The track switches are #10. Extremely user friendly. I don't see that sharper switches would generate a clearance problem. But I would surely think longer and harder on the subject before I installed them.
My trackage in that area does not have any scenery. So I don't have to allow space for it. That is also something to allow for. Or not. I would be extremely wary of placing telegraph poles in the foreground. If I did, I'd design the installation so that they dropped into pre-made holes. And I'd have plenty of spares.
All that said, the NMRA minimum spacing for HO tracks on the straight is 1 15/16". Or it was back when my sheets were printed. Anyway, 4 x 1 15/16 = 7 3/4 ". That is the absolute NMRA minimum. I would STRONGLY RECOMMEND that you build a little mockup before committing to this approach, though. And your curves will have to have much more clearance if they are in the 24" radius range. They WILL NOT WORK if you maintain 1 15/16" spacing through them.
At the front, you will have to decide how much fall-over clearance you want. You can be daring and allow for none. The Free-mo standard is that the centerline of trackage must always be at least 4" from the edge. A number to think on.
Ed
PS: I see various changes and additions happened as I was writing my response. Yeah, 18" is a piece of cake. But what I wrote might still be useful, so I'll leave it up.
Shock ControlEach shelf section will end with a 4' x 4' section for the trains to turn around.
If by "mid century passenger" you mean mid 19th century, this might work. If as I suspect you mean mid 20th century, probably not.
At the point where you enter the 4x4 turnaround, you will be creating an S-curve. These long passenger cars will need at least 12" of straight track before you can reverse the direction of the curve. This won't fit on a 4x4.
I have the right to remain silent. By posting here I have given up that right and accept that anything I say can and will be used as evidence to critique me.
The bigger concern is the blobs on the ends. They are 48" wide, leaving 2" clearance on the edges, that leaves 44" or 22" radius on the outer loop and the enner loop will have to be in the neighborhood of 19.5" radius. Very tight. Yes I know 18" is the "minimum" radius but remember that is minimum, the lower threhold below which bad things are likely to happen.
If you run long cars your operation will be less reliable. Large wheelbase engines, steam and diesel will be less reliable.
If you have the space and can go to a 4.5 x4.5 or 5x5 blob on the end, that will let the inside radius go to 24" and make things a whole lot easier to operate.
The max depth of the straight portions should be in the 30" range because its hard to reach over that. The minimum depth would be about 10" (four tracks on 2" centers with 2" to the edge of the benchwork. Widths of 16 and 24" are handy because they are fractional widths of a 4x8 sheet of plywood. Personally I would go with the maximum my width would allow, based on the rest of the room. I would try for 24".
Dave H. Painted side goes up. My website : wnbranch.com
ACYWe are assuming HO scale here. I would consider 12" to be the ABSOLUTE MINIMUM...A width of 18" - 24" would probably be more satisfying, if you can manage it. Tom
I would consider 12" to be the ABSOLUTE MINIMUM...A width of 18" - 24" would probably be more satisfying, if you can manage it.
Tom
Thanks, yes, I fixed my original post. I was hoping to do this in 18", so it sounds like it may be possible.
We are assuming HO scale here.
I would consider 12" to be the ABSOLUTE MINIMUM. This would allow 3" from the edge to the centerline of the first track, then 2" for each of the three spaces between the four track centerlines, then 3" from the last track centerline to the wall. If there are crossover switches in this stretch, you might find that the 2" track spacing has to be increased. A larger spacing might also be preferred to allow for the swing of car ends as cars enter the curves (the 4' x 4' turning loops imply pretty sharp curves). These factors would increase that 12" minimum.
This also means no extra space is available for lineside structures, industries to switch, etc. Extra width would have to be added for these.
A width of 18" - 24" would probably be more satisfying, if you can manage it.
I am planning an HO layout with an L-shaped shelf section along two walls. Each shelf section will end with a 4' x 4' section for the trains to turn around.
The layout will be primarily for continuous running. I am planning, essentially, two dogbones, one inside of the other. So, the outer dogbone will include the close and far track on the shelf, and the inner dogbone will include the two inside tracks.
I am running transition-era freights, and, occasionally, a mid-century passenger train on the outer dogbone. I plan to run two trains concurrently, one on each track.
So, what would be the ideal depth of the shelf section, allowing for clearances between the trains? I would also like for it to be deep enough to allow for a line of telegraph poles along the outside.
Thanks in advance!