Grades and Wyes


A

AL1

Shortliner
While designing my "dream" layout for the basement, I hit a couple snags as far as design goes, and need some advice.

First of all, there are multiple wyes that will be required on my layout, what should the minimum radius be? I would like them to be as small as possible without looking toy-like when trains use them

Second, from the main yard, there will be a pair of small(10' or so) representations of shortlines, however, I want them to be on a second level below the main level. How steep should the grade from the yard down to these other levels be? I would like to model at least one industry on each for operating purposes. How far down from the bottom of the main level should the second level start?

Thanks in advance.
 
Curves and grades

Well on my horse shoe curve I have radiuses of 26, 22, and 19. I have no trouble with the 19 as long as I don’t use over 50 foot cars. The helix grade is 3%. It takes 3 powered engines to pull a 32 cars train up the grade. One engine for every 12 cars. I would have made it 2% but I got tired of making the helix sections. I can add another section when I’m fully retired I guess. Then it would be 2%. If you want to take a look go to youtube and type in jvtrains in the search box. The coal train in the Janesville Branch video is using the 19 inch radius loop.

NYC_George
 
AL1, I'm not sure if you have HO or N scale, but this should work for either. The radii in wyes really have to do with what you are using them for. If you have it on a mainline and switching to different towns, then you would want at least a minimum radius to match those in your mainline curves. If the action is medium to slow speed, then you can reduce the radii accordingly. I have three wyes on the layout and each serves a different situation. I have one that is designed to reverse engines only at a slow medium speed and it has a minimum of 22" in the legs of the wye. Another with a minimum of 24" is part of the yard lead and that accommodates full freight trains, but at slow speed. Lastly, is a wye that is used for freight and passenger trains, but at reduced speeds; it has a minimum of 26".

Remember that a wye doesn't have to look like a perfect wye. You can have one leg straight and the other curving in or different radii in different parts. It all depends on your location and space. Just make sure you always maintain a smooth transition between the straights and curves. They do eat up a lot of space, so plan ahead for them.

Grade: I would recommend that you use the max of 2% recommended for HO or whatever N scale has. The main point here is how your engines can maintain traction. The steeper the grade the less traction = less cars pulled. If I remember correctly a clearance of 3.5" or more is the separation for levels, but I like more so that I can get my hand in there to re-rail cars or maintenance.

Did this help?:)
 
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I think the answer will be limited by the space you have and what era you model. I run 22" radius and number 6 switches. its still tight with current day long freight cars and 6 axel diesels but I mostly run med steam and cars found from the late 50s and before.

your idea of having an industry lower than the mainline is very prototipical.I do the same thing on my home layout and find it at the local club I belong too.You can get away with a much steeper grade here as you wont be pulling more than a few cars out of it. I think a 5% grade here is not a problem if the industry is 1 or 2" below the mainline grade

On my layout my industry is on the main level of the layout and the yard is a little higher just behind it. leaving the yard it again climbs before going into a straight 5' section to get over the lower mainline track.

hope you follow me here

trent
 
Well, I am modeling HO, the era being 1975-1982. Most car lengths don't exceed 50' aside from a couple of piggyback cars that will be 85'. None of my Wyes are for anything except switching, so 19" should be acceptable? Space isn't a huge concern, but I would rather not match the 36" minimum on my mainline.

The problem is I am trying to model a significant portion of a large city with lots of intricate trackwork. The two shortlines have their own yards, and I will model out to a single industry on both of them (just so I have an excuse to model Alco's and A&SAB GP40's). How can I hide a slow transition down a second level that will be at least 6" below the main level? How much space would be required?

Thanks again for the help so far.
 
Your 85' cars are your limiters. I would be stunned if they managed to negotiate curves under 22", regardless of the care and speed taken. Heavyweight passenger cars, in most instances, don't work when coupled together on curves less than 23". However, despite what I think, your best insurance is always to mock it up when dealing with marginal circumstances and do trials. The trains won't lie to you.

-Crandell
 
Selector said:
Your 85' cars are your limiters. I would be stunned if they managed to negotiate curves under 22", regardless of the care and speed taken. Heavyweight passenger cars, in most instances, don't work when coupled together on curves less than 23". However, despite what I think, your best insurance is always to mock it up when dealing with marginal circumstances and do trials. The trains won't lie to you.

-Crandell
Click to expand...

Only one wye will need to support the 85' piggyback flats, the others are interchange tracks but only for 50' boxcars and some hoppers (20" radius?). On the prototype, the wye is the end of the line, and used to turn the locomotives for the return trip..I could just include a passing siding instead, saving space and sharp curves.

Not sure if I will be including passenger service, 1975 is early Amtrak era, and the only train that would have run on my layout was the Floridian/Auto-Train (on second thought, those should be priorities on my layout! The Auto-Train's second route is what caused the company to go bankrupt and was run only briefly..).
 
You could probably use 22" for the loco turn around, less if you have the smaller diesels. I have some heavy steam that handles that well. (don't see how you can turn them around with a passing track unless you are referring to a run-around only.) You don't have to have that huge 36" on the others no matter what they are used for. For switching I would say at least 22" for 50' cars and 24-26 min for those monster piggybacks and any heavyweights. For any mainline higher speed traffic 26 and up. :)

EDIT: Crandell has a good suggestion about mocking it up and trying it. Just lay it out and temporarily secure it for the testing. I did this on one of mine that required some strange tracklaying, i.e. curve, straight, curve in one leg of the wye.
 
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RexHea said:
You could probably use 22" for the loco turn around, less if you have the smaller diesels. I have some heavy steam that handles that well. (don't see how you can turn them around with a passing track unless you are referring to a run-around only.) You don't have to have that huge 36" on the others no matter what they are used for. For switching I would say at least 22" for 50' cars and 24-26 min for those monster piggybacks and any heavyweights. For any mainline higher speed traffic 26 and up. :)

EDIT: Crandell has a good suggestion about mocking it up and trying it. Just lay it out and temporarily secure it for the testing. I did this on one of mine that required some strange tracklaying, i.e. curve, straight, curve in one leg of the wye.
Click to expand...

I was referring to a run-around, sorry for not making that clear. The other wyes are located in "urban" (well, as Urban as a mid-sized Alabama town can get..) locations and used for interchange only, so I will try for a 22" radius, maybe 24" if it will fit.

Thanks everyone for your help!
 
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