gradient and clearance

So I'm starting to play with designs and I've enocuntered my first constraint.

What is the suggested minimum clearance and maximum gradient?
i.e. how long a run do I need to have one track clear another?

According to this guidetozscale.com/html/marklin_track.html
article, it's 40mm and 4% grade (4mm : 100mm). That means any time I have a track go over another it needs to have an incline of no less than 1 metre. Is that right?


Wow, that's going to be virtually impossible to do on a layout that's only 2'x4'.


I should mention I'm going to run a steam loco and it probably won't pull more than 6 or 8 cars.

Here is the layout I've been sketching. (The actual sketch is much more detailed). I used the folded dogbone.

The grey shading is not mountains, it is just showing elevation of track above the baseline.

I'm concerned so far with whether the grades work. I'm worried that, when I go to build it, those grades will go much longer to reach the baseline than I have drawn. This will obscure more of the valley than I intended.

Input?

With steam engines you wpn't need the full 40mm, that's when using catenary. According to NEM102 you should have enough with 30mm. But 4% is pretty steep certainly on a curve.

I think you will find the grades much easier to deal with if you switch the two tracks on the right end of the plan, making the lower one on top and vice-versa. Then, the grades will run along the two long tracks at the top and bottom of the plan.

Something like this (download the image to see it all--it gets chopped off by the forum):



Note: only tracks changing grade are highlighted with grey. The grades are now a very reasonable ~1.5 inches over nearly 4 feet, or 1 in 28, which is negligible. And they are on straight (or nearly straight) runs. You should have no trouble running almost anything you want on those grades.

The front track now rises up above the canyon with the river/lake, so I'd suggest it be elevated on some type of bridge, such as a steel trestle; this will add interest and provide visibility to the scenery. The track along the back is then much lower than it was previously, which is fine as it now has a "peek-a-boo" effect as it passes through the rugged terrain in the river area.

Which steamer are you planning on using? You could apply the frog snot to non-pickup drivers (I''e the second driver set from the back of the locomotive..). They are not touching the rail head... but I think that with layer of frog snot they could improve adhesion and pulling...

Konrad

David K. Smith wrote:

Note: only tracks changing grade are highlighted with grey. The grades are now a very reasonable ~1.5 inches over nearly 4 feet, or 1 in 28, which is negligible. And they are on straight (or nearly straight) runs. You should have no trouble running almost anything you want on those grades.

The front track now rises up above the canyon with the river/lake, so I'd suggest it be elevated on some type of bridge, such as a steel trestle; this will add interest and provide visibility to the scenery. The track along the back is then much lower than it was previously, which is fine as it now has a "peek-a-boo" effect as it passes through the rugged terrain in the river area.

Hm. A very different take than what I was thinking but gives me some ideas.

The focus of the display is a village surrounding the pond, so it should be a large, flat bowl, not a gulch. It will be more gulchy up near the river head. There will also be some village on the mountaintop to the left.

This is a display that will be viewed only from the front so I'd like to keep the tracks in the front of the display as low as possible.

I will consider your changes.

kmalkowski wrote:

Which steamer are you planning on using? You could apply the frog snot to non-pickup drivers (I''e the second driver set from the back of the locomotive..). They are not touching the rail head... but I think that with layer of frog snot they could improve adhesion and pulling...

Konrad

Frog snot?

DaveC426913 wrote:

kmalkowski wrote:

Which steamer are you planning on using? You could apply the frog snot to non-pickup drivers (I''e the second driver set from the back of the locomotive..). They are not touching the rail head... but I think that with layer of frog snot they could improve adhesion and pulling...

Konrad

Frog snot?

Bullfrog Snot is a liquid that you apply to wheels (while they're spinning) to create traction tires.

www.zscalemonster.com/bullfrog_snot/

Sorry I did mean bullfrog snot...

Konrad

DaveC426913 wrote:

David K. Smith wrote:

Note: only tracks changing grade are highlighted with grey. The grades are now a very reasonable ~1.5 inches over nearly 4 feet, or 1 in 28, which is negligible. And they are on straight (or nearly straight) runs. You should have no trouble running almost anything you want on those grades.

The front track now rises up above the canyon with the river/lake, so I'd suggest it be elevated on some type of bridge, such as a steel trestle; this will add interest and provide visibility to the scenery. The track along the back is then much lower than it was previously, which is fine as it now has a "peek-a-boo" effect as it passes through the rugged terrain in the river area.

Hm. A very different take than what I was thinking but gives me some ideas.

The focus of the display is a village surrounding the pond, so it should be a large, flat bowl, not a gulch. It will be more gulchy up near the river head. There will also be some village on the mountaintop to the left.

This is a display that will be viewed only from the front so I'd like to keep the tracks in the front of the display as low as possible.

I will consider your changes.

The only way to keep both foreground tracks low is to switch to a true folded dogbone (your original plan is actually a twisted dogbone--it would be a figure-8 if it was unfolded). The only downside is that it is a bit less interesting-looking than the twisted dogbone, which provides more variety in track heights. The advantage, however, is that grades can be even more gentle than in my first revision of your plan; here, the run is nearly doubled to rise the same amount as before. Plus, it's simpler to build.



Note that I don't know if the geometry of existing sectional track products can support the plan exactly as drawn--I just tossed this sketch together to present the concept of a folded dogbone. It could certainly be done as shown with flex track, anyway.

Yeah, this regular folded dogbone is what I'm working toward. Even though I'm just sketcfhing right now, I can see that it's going to be a lot of flextrack. Now way I'll be able fit it on the layout and maintian standard sections. In fact, I'm already needing to add a few inches to the depth of the layout.


Something I'm curous about - this whole layout only rises about 6cm - highest track elevation is a mere 2.5 inches. Does that sound right?

DaveC426913 wrote:

Something I'm curous about - this whole layout only rises about 6cm - highest track elevation is a mere 2.5 inches. Does that sound right?

Depends entirely on what you use for subroadbed. The height difference between lower and upper tracks can be as little as 1 inch, assuming the subroadbed in just the areas where the tracks cross is an absolute minimum--say, thin styrene or sheet metal. If you run the subroadbed over the lower tracks, then the height difference between lower and upper tracks would be about 1 inch plus the thickness of the subroadbed, give or take.