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I plan on using 1/2" birch plywood for my sub-roadbed. Grades will be about 3.3%. My risers will be approximately 16" apart. I was planning to add a single center spline of 1"x 2" for additional support. Am I over engineering this? What is the recommended spacing for risers using only 1/2" plywood? Risers will probably be cut from 1" x 4" stock. Sub-roadbed will be 4 1/2" wide.

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Choo Choo kenny posted:

    Keith get your heaviest engine and put it in between the risers and see if the birch plywood droops down. If it does add the extra supports in between the risers. When I did my grade I put risers every 12in. with 1/2in. chip board and I don't have any problems. Choo Choo Kenny

Thanks Kenny. I'll do the test when I get there.

   It seems 1/2" would be plenty on solid risers (especially with foam added?) I used 1/4" (?random type) with tubular on an El with Lionel trestles, and have two 16" spreads, there is some flex with a PW Hudson or GG-1, but very little. If I don't park them there, I don't see it ever being an issue.  My plywood knowledge among different wood types is limited, and of birch ply., is nil other than its light.

  I don't know if your doing a single full sheet that's bent to position, or a piece by piece build up, but it's worth mentioning that the grade should gradually increase. 

    The base and the crest of the hill should have less grade, and the middle of the climb, a steeper grade. If you averaged 3.3, you will likely actually need more like 3.8 at the hills center (3.8? no real math done there).

 The reason is, abrupt coupler angle changes can cause uncoupling. If the track in the open space between trucks on two cars, rises too quickly, it creates angle change at the knuckles. Long coupler shafts can make it worse. So do use those longest ones to test with too before you lock things down 100%.

    The 2% is for added realism, and very long trains. Most motors can pull up that grade ok; the traction is the real issue.

   To put things in perspective a little, My E-33 can climb a 7" 14', 5% grade with about 8-10 Lionel hoppers, and a caboose. It's 0-27 going in and out of the grade too, those tight curves add to the load. One magnetraction PW-SW can pull near the same (7), another PW-SW, one with rubber tires, can only pull two cars. A modern one 3-4. PW Steam needs magnetraction for that hill, and is limited to 3-5 cars.  About 3 small, light, engines need a good running start to make it up with a load. 

    I made a mistake zeroing a digital level and measuring. I ended up with 3.7 on one wall, 4.98 on the other   Still, it makes for a good loading challenge, so I climb the steep one 90% of the time

  Oh, I forgot... To increase traction later, I added 2-sided tape to one outside rail along the length of the 5% grade. The tack was deadened with use quickly, but it provides a better grip, and really can't be seen without looking close. Before that there was a couple of starter set loco's that couldn't do it at all, let alone pulling. The same tape has been there near 7 years now too.

   Adding weight helped to solve the starter sets traction issue pretty easy.

Also- I use mostly tubular, but my Super O is nearly flat rail, and seems to give better traction than my tubular, magnetic loco or not.

Adriatic posted:

   It seems 1/2" would be plenty on solid risers (especially with foam added?) I used 1/4" (?random type) with tubular on an El with Lionel trestles, and have two 16" spreads, there is some flex with a PW Hudson or GG-1, but very little. If I don't park them there, I don't see it ever being an issue.  My plywood knowledge among different wood types is limited, and of birch ply., is nil other than its light.

  I don't know if your doing a single full sheet that's bent to position, or a piece by piece build up, but it's worth mentioning that the grade should gradually increase. 

    The base and the crest of the hill should have less grade, and the middle of the climb, a steeper grade. If you averaged 3.3, you will likely actually need more like 3.8 at the hills center (3.8? no real math done there).

 The reason is, abrupt coupler angle changes can cause uncoupling. If the track in the open space between trucks on two cars, rises too quickly, it creates angle change at the knuckles. Long coupler shafts can make it worse. So do use those longest ones to test with too before you lock things down 100%.

Birch is one of the stronger and better plywood. I set the grade at 2%, for the first 40" from flat (top and bottom), so I can create a transition. After that it is about 3.3%. I am using a solid 1/2 " ply where the grade is consistent. At the transition ends I will use 1/4" or thinner laun (I think that is the term).

Oman posted:
turbgine posted:

Is it necessary to use 3.3% grades? That is a pretty steep rise. I was taught to limit grades to 2%. This rule has never failed me and it looks realistic.

Necessary for the layout that I created. My bench is only 8' x 18' and 11' wide at one end. Everything is a trade off, unless one has unlimited space.

3.3% isn't that extreme for a model railroad.  2% is an arbitrary standard, maybe good for huge layouts running huge trains.

Last edited by Ace
Chooch posted:

Moon man, amazing, a sagulator? A method of converting percent of rise into angle risers? Amazing!!! You get the praise for most useful information. Thank You, Chooch

The internet can be a wonderful source of information. Someone challenged the strength of a shelf layout with brackets on the top. Well, the sagulator was found to dispel part of those misunderstandings. I am just too lazy to do the math these days, so I had to find the calculator. Note that the sagulator is for a constant load.

We all work in percent for slopes in model railroading (the math is easier), but I needed the angle to set my miter saw for risers. Lo and behold, the converter was on the 'net. I see many use flat risers for grades. Mitering the top for the grade made setting the sub-roadbed much easier. Alex (Ingenerio No.1) brought this to light for me in his 2011 layout build. In real railroading, the engineer's work with angles when determining grades, curves and such.

So, I learn and share. I hope it helps someone.

Last edited by Moonman

I had done this several years ago, It is difficult on a small layout to get grades less than 3%.  Even with the curves, 12 ft to 14 ft of run for an 7" rise is the best you can do.  It works well with multiple powered units.  Surprisingly down/speed is more difficult than up. 

The 7 inches allows for a tunnel on the lower level.  There are only a couple of sections of the outer loop that are level.  Most of the loop is either rise or fall. 

Last edited by Mike CT

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