Hi all,

I'm currently in the process of designing a layout for my father. The trackplan is already decided on, and now I'm making assembly drawings in AutoCAD to make the base structure. Since my father is not that technically skilled I intend to make IKEA like instructions so that if he follows the plan he will get a perfect layout. This means I need specify all dimensions correctly in the plan.

My question now is this, what is the maximum slope I can allow?

As a baseline I would like to be able to pull my metal Rheingold coaches over the slope without issues. The layout basically has 2 slopes, where the trains can enter a hidden station. It will be made in C-rail, and consists of 12 pieces of 180mm straight track (actually the 172mm & 188mm mixed but whatever). Say I need 100mm height difference over that distance (12*180mm=2160mm) the slope would be 4.63%. It looks like this in a diagram (purple line), the Y-axis indicates the height difference in mm, the X-axis the distance, also in mm:



The problem is (I think) that I cannot go from a 0% slope to a 4.63% slope. I need to smooth this one out and gradually increase/decrease the slope. For this I calculated the red slope, which is based on the sigmoid function (y = 1/(1-EXP(-x)) ).

You can clearly see that the difference in slope is much less, but the maximum slope (around 1080mm) is much worse.

Do you have any opinion about what the maximum slope can be and what the maximum slope difference, from trackpiece to trackpiece, is allowed to be? In my example in the diagram the maximum slope in the middle is 7.4% but the maximum difference from track to track is only 2%. If I lower the maximum allowed difference the maximum slope in the middle goes up.

Someone clever might say that I should increase the distance or decrease the height, well, I haven't got the space for it .

If you are interested, I can post the openoffice calc sheet here too.

Bert

I have found that the slope of 4% is the most that is workable. However that is only part of the problem.

The slope should be smooth and even. Transition points in particular can be troublesome.

Most steamers have a fairly fixed undercarriage and this length is the problem That I encountered. if there are any dips or rises, I found that the steamers will hand up with driving wheel spinning and no movement.

I found using Woodland Scenics Pre Formed 4% Foam Risers works better for me. You have four sections that togethr are eight feet long and work very well.


I am covering the top of the foam risers with thin balsa to provide something to secure the tracks to.


Just my 2 Cents,

Bert One way is to try before building. A length of wood on the floor supported by books to increase the height at one end (thin books will increase the height by small amounts) lay your C track and run the locos you will use with their maximum weight being pulled and see how high you can go before the loco slips.
This I know is to say the least basic but does work.
I agree that the Woodland Scenics ramps are good although a bit expensive.
I presume a helix is not possible.

For the start of the slope, the transition from level to uphill, I find wood shims work very well. Just cut off the length you want. Woodland Scenics has incline starters which I imagine would do well for the transition - I will be trying them on a layout I will be constructing soon.

Dan

Bert, as others have suggested, the transition points are most important. Steam locos in particular can have issues if the transition point is too sharp - they go light on the front bogie and will derail. There is also a good possibility coaches will uncouple. Try to keep the transition points on a straight bit of track if you can to minimise all of this.

Check the Marklin catalogs in the bridge section. There are recommendations there for pillar heights. Also in hidden area you could use threaded rods for your risers. That way you could make adjustments easily if needed.

Hi,
Your plan for a gradient needs simple track planning rather than maths. If you want to run a heavy train such as the Reingold with 5 coaches you will need a very gentle slope more like 3 degrees, it also varies with which engine you use as their pulling power is variable. The only way to test is to build an experimental slope of varying heights and see what suits your setup. ie the slope will need about 12 pieces of track. On my analoge M track layout my slope is closer to 4 degrees and my da 800 loco just manages a 3 coach load. I dare say it is different with c track but with m track having curves in the slope needs extra careful track alignment to a avoid derailments and limits the speed if you need to "rush" the slope
regards

Bert,

regarding curvature on ascents/descents, I needed to bank the curves to avoid truck derailment with my GG1:

https://www.marklin-user...ult.aspx?g=posts&t=10574

"A little bit of curve banking solved a problem I had with the GG1 on ascending/descending curves (~4% slope).

I first noticed that on ascending a curved track section (R2), the GG1's front wheels of the front truck jumped the rails. On a descent, this also occured and sometimes the front wheels of the rear truck also jumped. The jumps did not occur at a track junction but partway along the track. This didn't happen with other locos (steamers - BR86 and BR50). I also had no problems with the GG1 on unbanked level R1 and R2 curves."

Dan

Yes, locos w/o load regualation slow down in curves.
In curves the tractive power of the loco is weaker. Go for wide radii if you can't avoid curved slopes.
On double tracks, use the outer track for uphill.

Tom,
" left school some decades ago but IIRC 4° are almost 7%"

Well I don't know what that means.. but I dare say you are right. The point of the matter is the gentler the slope the less potential trouble you are goung to have.Also building an experimental slope to test out your ideas is really a good thing to do.
regards

It means - I guess - that if he remembers right, a 4 degrees slope is 7 cm on a meter. That is correct, and that is very steep.
I've got a grade of 10 cm in 2.5 m which most M* locs can manage even with a heavy train (e.g. a BR18 Rheingold with 5 coaches, which is not a good puller, or a BR96 with a heavy 2.5 m. train). On the other hand, an Electrotren NS 1300 does not manage this, in spite of its many powerede axles. Something inside goes wrong then (plastic gears ??).
So I guess 4% is about the max., 5% when running only light trains.
The M* bridge elements only do about 2% (4 mm per element).

I think the suggestion to use short track element in the beginning and in the end of the slope is very good. For best pulling results it's best not to have different angles in every piece of track since every change of angle will result in a spot of bad pulling!
Rgards, Henk

Such a steep slope is far beyond all recommendations, but I had 5-6 % gradient in R2 curve (437.5 mm), and I had no problems with large locomotives with good and clean traction tyres and 4 coaches or about 10 freight wagons. If your 7 % slope is on straight track, it probably works with some train length limitations. But even if it worked for me, I do not recommend that kind of potential problem source. You should make a temporary test slope with simple cardboard structure and test those trains which you want to use before you make a real layout.