I continue to refine a 5’7" x 10’ HO layout that is basically a 2-level folded dogbone single mainline, with an upper and a lower reversing loop, a long passing track and a couple of yards. I think the radii are 26" or more outside of yards.
I see the first big commitment in ordering the turnouts and related flex track, and want to know I’m really ok with the overall design before ordering the turnouts!
The biggest checkpoint probably is that the upper and lower sections are connected with a 2-1/4 percent curved grade (4" rise, about 14’ long, 26"R or so). Is that within reason (not too steep)? Otherwise I’d have to go to a different plan.
The second key decision is for main & yard turnouts, if someone can confirm my understanding. The main line, crossovers, passing track & reverse loops would use 7-1/2 curved turnouts and one straight #8 so no problem for most rolling stock I presume. But the yards I’ve laid out would use #5 turnouts (vs #6) for space reasons. What gets my attention is the chart in Track Planning for Realistic Operation that shows Closure Rail Radius as the most demanding issue…in the case of #5 at 26". So it seems that’s ok…#6 might be visually more realistic but takes more space. So the key issue for rolling stock might be the 7-1/2 curved turnouts with the nominal inside radius of 28", which some have noted may be closer to 2-3" less for code 83 Walther Shinohara.
I’d appreciate views on the above items as I don’t want major hindsight on these issues after spending the bucks on the associate track that pretty much will lock me into this design.
The radius is a bit tighter than I would like, but the grade isn’t so bad. Put it this way, many have had to settle for a lot worse. I think it is probably reasonable if your cars roll freely, are well coupled, don’t weigh too much or too little (either case could be a problem on tighter curves on a grade), and you have enough amps and traction to pull it all up the grade without spinning. You don’t want to have the locomotive wearing the plating off its drivers, and if you put to much of a test on it, that’s what will happen.
If you can do it without a huge amount of bother, try spending a couple of hours to mock it up accurately and try your longest trains. If you succeed, and don’t end up with a steeper grade in your elevating grade, you should be okay.
The turnouts you describe should be good for just about all typical passenger cars, although it depends on their condition, coupling, ability of their trucks to pivot cleanly, and the diaphragms, if they are present, are not too stiff or don’t stick out too much. I mean this on the inner route of the curved 7.5. I have those on my layout, the Walthers/Shinohara versions, and found their route radii to be overstated by over two inches!!! So, I had to cut the webbing on the two routes and widen the curves by quite a bit. Fortunately, they didn’t mind, and my cars and locomotives have given me no grief. All except the maybe the largest fixed-frame steamers in brass will be good on the #8 turnout, but I bet they would be fine. I use #6 turnouts in my yard, Pecos, and have no problems whatsoever, not even with a brass 2-10-4.
A good answer above, but you don’t say what era or type trains you will be running. More recent era, bigger locos and longer cars, need wider curves. Long trains are harder to pull up grades and are more effected by the curve of the climb.
Curved turnouts are more likely found on model railroads than actual ones. Of course the 1:1 builders usually don’t have the space limitations that we do, so there are times that the only way we can effectively “fit” a track plan into our space is to use a curved turnout. I had one on my previous layout and none on the current one.
In that curved turnouts aren’t as common even in the model world as “regular” ones, I offer a suggestion based upon quite a few years of HO modeling experience: If you utilize a non-standard turnout, set aside an extra one of that same brand and curvature if you can at all afford to do so. These things can fail at places that are difficult to repair, and if you have another one set back, you can replace the problem without shopping for something out-of-production or something similar from a company still in operation.
Good luck - it will feel good to get building and then operating!
I predict that you will make some mistakes. We all do. But, you shouldn’t let fear of making a mistake stop you. You can plan for 2 more years, and you will still make mistakes.
A mistake, after all, it just another name for a new modeling opportunity.
when calculating grades you have to compensate for vertical easements and curves. The resulting grade will be about 4%. Subtract a foot at the bottom and a foot at the top of the grade for easements and you’ll have 4" of rise in 12 feet. The compensation for curves is about 32 / 26 = 1,15%. Not knowing the length of your trains, nor the motive power…it could be an issue.
You do not give any information about the kind of equipment you want to run. For modern 89 feet long auto-racks #5 turnouts are in line with your radius, but not the right stuff. Especially when pushing is involved you might be in trouble.
Last but not least, if your layout is build on a huge 5,5 x 10 table you will have severe access problems. Not only for building and maintenance, also probably for (un)coupling. If coupling is not done manual you have to place your magnets on almost straight tracks (radius = 5 times or more the length of your longest cars).
