O gauge grade question

[cobra2411]

As a kid I had a Lionel O-27 set and after almost 30 years the bug bit and I have 3 MTH sets. They are: a Delaware and Hudson Alco PA ABA set with 6 cars, an NPK Berkshire 2-8-4  with 10 cars and a Harley F3 RTR set (loco + 3 cars).

I'm planning an 8 x 16 generic mountain pass layout with two tracks. The outer one will be an O-48 track in case I upgrade to some Premier or similar trains that require larger curves and the inner track will be an O-31 track. 

Anyway, the O-48 track is going to climb over the mountain, the O-31 is going to go through it. If you look at the 16 foot long section as the front/back, the front is going to have straight track and then go into a 90 degree turn, down a short straight into a 165 degree turn, then to a 150 turn the opposite way around the outside of the mountain and back into a 165 degree turn, back to a 90 and then down the straight again. I want it to climb the mountain as it goes so I can pass the O-31 track through the mountain underneath. 

What kind of grade can the Berkshire climb with 9 freight cars and a caboose in tow? At first I was thinking a 5 degree angle, but that's around a 9% grade. It is a mountain pass, so I want it to look like one, but also I don't want to kill the trains. Is a 5% grade out of the question? Should I go lower? 

I was thinking of elevating the front straight of both tracks and having the outer loop climb from there and the inner loop descend into the valley so to speak. This way I have enough vertical clearance for the tunnels. Also, that should make the mountain pass look higher than it really is without having a crazy grade. I think I can do that with around a 3% grade. I have about 450" of track to go up and down so that would allow me to gain about 7" over 225" of track and by dropping the inner track that gives me plenty for having a tunnel. At 4% it's about 9" rise and at 5% it's over 11". I really want that up in the mountains look and feel but I don't want to have problems running these trains or any future ones I get. 

Thanks,
David 

[JoeinPA]

David:

Most of us on this forum are in HO or N scale and since you are interested in both pulling power and grade you will probably get better answers on the Classic Toy Trains forum.

Joe

[selector]

David, no matter where you ask the question, the answer from those who have learned how to make trains work in any scale will always be the same...it depends on traction and hp.  Your scale lomotive has the same problems with a 3% grade as does the equivalent scale locomotive in HO on the same grade.  They both have to have the ability to apply power to the rails via tractive effort....friction on the rails sufficient that the power makes the whole train move up the grade unassisted.   If it can't, you have two choices...reduce the grade or apply more power/traction.  It's easy to just add a pusher or another loco on the head end.

In the real world of trains, as little as a half-percent of grade requires more than three times the hp as it would need to keep the same train moving on level tracks.  With that scary thought, no wonder railroads were inclined to look for winding grades that were less steep.  The tunnelled when they had to keep the grade below 3%, or they went around hills, or they zig-zagged up valleys using switchbacks and tail track switchback. 

For your case, you should satisfy yourself by mocking up a plank with a system where you can objectively and accurately measure the grade.  Place track on it, power it, and see what your locomotive can handle.  At some point, you'll know precisely what your steamer can do and what it won't.  If you add a curve, you'll almost certainly have to reduce the grade a bit.  Once you know what combo of grade and curve you can get away with, from there you can place that combo in your defined space and figure out if it can be used.  Anything else will have to be a combination of a reduced curvature and gradient...no ifs, ands, or buts...

Crandell

[rtraincollector]

Just another comment I'm building a layout the same size as you 8' x 16' I went with O-72 for my outside rail as you better watch out should you get any scale Atlas a lot of them are minumum O-54 curves. I found out after buying befor I was even in the planning stages but it told me I had to have at least O-54 I'm doing O-72, O-63, O-54, then O-31 super O and then a figured 8 in O gauge O-31

So I'm ready for the bigger engines should I ever need it I can go up to O-72 as there is some out there that do that and even (Gulp) O-84 but I passed on that.

[Buckeye Riveter]

RT...Good choice to use those 72" curves.

As to grade, I use 2.5% (2.5" of rise for 100" of run) and only the locomotives without traction tires have trouble climbing the grade.  When you place a curve into an upward grade, it takes more tractive effort. 

[charliebrown]

I started a thread on a trestle system and my locos having issues climbing. The things I learned from the group here ....

A - you need wide curves

B - the stock trestle from manufacturer is to steep

C - if you plan to run long trains the grade needs to be super low

D - (this is something I figured out) when planning your grades,tunnels,and curves consider future locos

[KRM]

I was advised to use 3/4" per foot of rise on this forum and I did that. It works but in looking at it now I would of gone with 1/2" or less per foot of run. JMHO

[cobra2411]

I'd love to do O-72 Curves but it's going to be tough with the design I have and keeping it all in an 8x16 platform. So O-48's are going to be it for now...

I'm thinking 1/2" per section max for now. Probably 3/8" per section.

[cobra2411]

Ok, so I did a little testing. I setup a nice loop track with about 8' long straights on some strips of plywood that I can and elevated the ends. I then grabbed about 13 cars and hooked them up behind my MTH Alco PA and later behind my NKP Berkshire 2-8-4. I then elevated the track.

Both trains were able to pull the load of cars up the highest grade I made, about 5%, but they were not happy. The Alco did a better job but in the end I would not pull that many cars up that grade. The Berkshire, even with traction tires spun trying to get the cars rolling on the hill. The Alco derailed when I tried to get it started on the top of the hill into the turn. The trucks rock back and forth around the center axle and the best way I can describe it is that it wheelied. The front of the truck went hard up against the body and as it entered into the turn the front most wheels jumped the track.

I worked out some numbers for people that are wondering how to make their grades:

1/2" per foot is about a 2.5 degree angle and is about a 4.4% slope.
3/8" per foot is about a 1.8 degree angle and is about a 3.14% slope.
5/16" per foot is about a 1.5 degree angle and is about a 2.6% slope.
1/4" per foot is about a 1.2 degree angle and is about a 2.1% slope.

I was a little over 1/2" per foot (.60") and both engines made it up and were able to get started on the grade. I would stick to something around 5/16" per foot unless you are modeling a mountain pass, etc.

[dsmith]

On my small layout I have been using the standard Lionel elevated trestle set that rises 5" in 8' or about 5% grade(which is very steep).  I use only 027 track with 027 curves and about half the track on the incline is curved.  There are two problems when traveling up an incline, one is traction power of the engine and the other is stringlining(derailing cars on an inclined curve).  Both are factors when traveling up an incline and is the same problems that real railroads face.  Real railroads add additional engines when traveling up an incline and you can do the same with model trains.  To help reduce stringlining, always place heavier cars toward the front, and check that wheels are clean and rotate freely and lubricate if necessary.  Here is a video of my layout running only postwar engines and freight.  Engines with magnatraction can pull up to 8 light cars or 4 heavy ones before the wheels begin to slip.  The second video shows 2 engines (one with and one without magnatraction) pulling 15 short boxcars up the same steep, tight incline without slipping.

 

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[RAVL]

When I have built layouts with grades, they were generally pretty large (16 x 24 in one case) so that I had plenty of run to accomodate a gradual grade in the range of 2% to 2.5%.  At that gradient, most of your trains will run fine and you will not strain locomotives or cause other issues.  You also want to keep the gradient turns as gradual as possible.  O31 will be a challenge in this regard, but you should be OK at 2%.

But your approach is sound -- experiment to see what works in terms of gradient and to see whether the equipment you want to run is "happy" at that gradient.  Some of the locos will never make any grades, and that's fine as long as you knew that on the front end of the project and are not disappointed on the back end of the project.