First a bit of background (I'll try to keep it short). I'm new to the hobby, and I've been tossing around ideas for my first HO layout, scratching stuff out on paper, playing around in XtrkCAD and generally doing a lot of reading. So far the only thing I'm pretty sure does *not* interest me is any sort of point to point layout - at least not one that is limited to that. I want a couple mainlines that make a full loop, sprinkling branch lines with industries, modest yards and the like where I can and sidings/passing tracks wherever I should. I like all sorts of trains, so I won't be concentrating too much on period-correctness (beyond the roster of a given train), so you may see an early era steam loco pulling a few short cars from an old saw mill at one end of my layout and a modern era Amtrak passenger train pulling away from the station at the other. Some may scoff, but it is what it is. I've got room for one good-sized layout, so it needs to be multi-faceted. I've got about 16'x7' to work with in my garage (I know, there won't be any environmental control aside from a space heater while I'm out there in the winter time, but like I said, it is what it is). I thought this was going to give me all kinds of room to do what I wanted, until I started laying it out. A couple of things I am really hoping to acquire to run on it some day are a Big Boy and/or Challenger and a modern passenger train. In perusing one of Joe Fugate's articles in MRH, he showed how 41-58" radii (the more the better, obviously) are really what is needed to get the longer (say, 100') passenger cars to look good on curves and at least 35" just to make them track reliably. Here I thought I would be doing well, if I went with 24"! The Big Boy looks like it requires a minimum 22" radius, but how reliable would that be, and would it have a lot of unrealistic overhang? I guess I could just avoid the 100' passenger cars, but what about those monster steam locos? Do you folks who have similar space constraints as mine just not run any of the long stuff?
I am not familiar with ANY 100 scale foot passenger cars unless you mean multi-unit. Longest I know of is about 85 feet. You mentioned 35" radius. If you have a 7 foot wide space, and go with 35 inch radius, you can have an end turnback curve with 70 inch diameter, center-line to center-line. Add about an inch on the outside EACH SIDE for width of track and roadbed beyond center line. 72". That leaves 6 inches each side for scenery or structures outside your continuous loop. You could add a second track outside that first loop for a double track main, though it wouldn't leave much AT THE ENDS. But track can come in on long middle portion of layout for passing sidings, yard tracks etc. Also don't forget that although you may need a large "minimum radius" for your least restricted mainline, you can always have sharper track elsewhere that is used only by a switcher and a few short cars. "Everything" doesn't have to be at "minimum radius." If you really want to be able to run larger possible loco, go ahead and "bite the bullet" and dedicate your layout specifications to do that and do it well. We ALL have space restraints, not necessarily the same ones because we are not trying necessarily to do the same thing.
The other thing to keep in mind is the value of scenery to disguise any overhang due to tight radii. Stay as big as possible, and with trees and building at the curves, the eye will be drawn to your long runs and not the curves
Rick, that's a good idea. I'll keep that in mind. Kenneth, you're right. The passenger cars referenced in the article were actually 83'. Don't know where I got 100 from. Looks like it's too late to correct my original post. Also, and I probably should have mentioned this up front, I'm looking at a dog bone type layout for the outer main line with the long straight run against a wall, sort of like the below image, with the lower center horizontal track not connecting with the upper, but a couple feet below it and parallel. The inner main will run inside of that, connecting to it where necessary and providing access to branch lines, yards, etc.
Many an HO full length passenger car will, like the Big Boy, bend itself around a 22" curve. And like the Big Boy, it won't look right doing it. I'd strongly recommend an absolute minimum of a thirty inch radius for your main line. And try to go wider if you can.
You say your space is 7 x 16 feet. Does that include space to stand OUTSIDE the layout? Can you get to "back side"? I have become in favor of around-the-room layouts operated from space in the middle, where you can NEVER see entire layout at once. You always see a scene with train running through it. For maximum size equipment like Big Boy and full-length passenger cars, Trailer-train 90-foot flats, etc in minimum space, this gets it-- at of course the cost of a duckunder (quack quack) or hinged up-or-down section. As far as hiding overhang of big locos on tight curves, viewing from INSIDE the loop makes cars and loco seem to couple closer together than they are at centerline, while viewing from outside the loop (on an "island" layout) accentuates the undesirable overhang. I like the ability to run continuous loop (but also point to point), but prefer NOT to be able to see both sides of layout at once where the loop nature is obvious. For an "island" layout, I prefer ability to move all the way around, have a viewblock down center, so you can only see one side at a time. Just my personal druthers.
I'm going to have to consider your island with a partition suggestion. Try as I might, I'm having a heck of a time coming up with something that meets a reasonable minimum radius for my needs, while keeping everything accessible, without splitting the space up. Not helping is the fact that, after taking another look at the available space, I'm likely going to be able to devote no more than about 14'x6' of it to my layout. Reason rears its ugly head.
Generally most modelers want a marginally dust controlled room for a layout. Is your garage finished in any way? You may want to consider putting up some dry wall and a ceiling. For the record my only space available for modeling is a low ceilinged basement and it's not climate controlled in any way at all. The traditional approach for a layout is the big table in the middle of a room style of layout. These take up a lot of space and do not provide as much square footage of layout as other types of layouts. The shelf style layout on shelves around the edge of the room may give you more square footage without taking away the inner space of the room for other things. If you take a 4x8 plywood slab and cut it into 4 one foot wide pieces and make and square out of them, you get an idea of the added amount of modeling and running space you get from the same square footage. It's also posible to mix the two styles of layout by running mainlines along walls and then putting a big yard and city scene on a table inside of that. round the walls mainline with a peninsula layout. One thing I see on a lot of shelf layouts is the double (over under) oval. With your room size of 16x7 an oval would be roughly 16+7+16+7 = 46 feet long. you'd use some length on the curves, but you get the general idea of it. If you did an over under you could get somewhere close to 90 feet of run into that. This would come out to a scale mile and a half, which isn't too bad in HO scale. A plan for a double oval with a double length mainline. In your case, if you built a shelf layout, you'd be standing in the middle of the ovals. http://tse4.mm.bing.net/th?id=OIP.M81c9ba3adeffc59a978cf9de9fcd53d5o0&w=300&h=300&p=0&pid=1.7 A lot of model railroaders like a double mainline, but a single mainline with passing sidings ads more interest as opposing trains have to be run around each other. I realize you like the water wings plan, but I am just offering some ideas.
