What is realistic grade for riser

Some thoughts...

First, grade is independent of scale. A rise of say 1/4" per foot is the same grade in O scale as it is in N scale.

Next, this sounds like a cliche, but it all depends... A curved grade pulls harder than a straight one, so you sould have to account for that. Your train length and locomotives would be a good determining factor as well. How high do you "need" to go? If you are doing a cross-over, I'd guess something around 2" would be enough clearance.

I'd set up a piece of track on an inclined board and do some test runs. The

1/4" per foot I mentioned before would be about 2%; a half inch per foot would be around 4%. I would think that anything much steeper than that would look "toy-like" UNLESS you were modeling a rustic lumbering line. In that case, steeper grades would usually be the norm. Like I said, it all depends.

One other thing that you want to consider when creating your grades... transition. When I built my layout, I didn't account for this and had some real troubles. Here's what happens... if you don't allow for transitions, your locomotive is moving along then the front end suddenly kicks up onto the grade. This causes the back end to drop and if the couplers of your locomotive stick out some distance, they can drop far enough to cause the car to uncouple. The same thing in reverse happens at the top of the untransitioned grade. The locomotive tops the hill and the rear end pops up, again, possibly enough for the cars to come uncoupled. So make sure that your inclines are flowed into and out of smoothly. If at all possible, try not to have a track joint at either the beginning or the end of the incline. Flex track comes in real handy here.

If you are having trouble understanding the transition I'm talking about, think of it in terms of driving your car onto an incline... if the incline starts abruptly, the front of your car goes up and the back end drops down, sometimes dragging. That is about the best I can describe it w/o being able to attach a drawing.

So get out those cars & locomotives and see what works well for you. Good luck!

dlm

This is like asking "How long is a piece of string?"

Railroads ran with grades as steep as 1 in 19 to less than 1 in 1000,

-- Cheers

Roger T.

Home of the Great Eastern Railway

First, in any scale, grade is rise/run x 100, which gives you the "percent grade." thus, 1% means 1 foot in 100 feet, or 1/4" in 100 x

1/4", which is 24.5", or about 1/8th of inch per foot.

Second, in any scale, including full size, grade affects how much the loco can haul, and the effect is drastic. Real railroads try to keep grades around 1% or less if possible, but even a 1% grade will reduce the hauling capacity of a loco by 30 to 50%. That's right: _half_ as much as on the level.

As for N-scale: if the locos have traction tires, you can easily go to about four percent (ie, 1/2" per foot) and even more. If they don't have traction tires, stay at 2% or less if possible (about 1/4" per foot.) You need about 1-1/2" clearance from railhead to overhead obstruction.

Dan Merkel's answer also has good advice.

HTH&HF

Good information. Thanks for the input.

OS

OK, I give up -- what happened to that other half inch? :-))

J. Bright

For my vertical curve ("transition") tables, see:

Not to put down the tables but these sort of things remind me if a story at the Canadian Railway Museum, way back when it was starting.

The volunteers were laying their first lengths of track. The CPR had staked the centre line of the curve and the volunteers had laid the ties out over the sub ballast and were now placing the rails onto the ties. The problem was, how do you bend the rail to the correct curve to fit on the ties?

The guys were business men, university students, lawyers, doctors, tradesmen etc.., etc., and none of them had any railroad experience. So here they were puzzling over how you bend the rail to the correct curvature. Some of the more mathematically inclined were try into calculate curves and other mathematical formulae using their slide rules. While this was going on, another new volunteer showed up. He was an older fella, in his mid 50s with the look of a working man who'd spent all his working life outdoors. He asked what they were doing and they explained how they were having trouble figuring out how to calculate the curve in the rail so that it would hold it's position on the ties so they could spike it down.

He said, "Like this" as he walked over to the end to the rail, grasped it with both hands, and slewed it into position on the ties. He was the Montreal Terminal track supervisor for CPR.

The same can be said of the vertical curve at the top and bottom of the grade. The road bed will form a suitable curve all on it's own thanks to the natural flexing of the plywood. Let it form it's own curve and then place risers under the naturally forming curve, do not force it.

-- Cheers

Roger T.

Home of the Great Eastern Railway

Wouldn't work with spline construction or the foam risers a popular scenery material supplier sells though. The layout builder would be dependent on fabricating a reduced grade for a short distance with the spline shape or foam risers. There would be some guidance from the track if flex track was being used, but there would be some challenge avoiding sudden grade changes with old fashioned O/027 sections or the roadbed track that is becoming popular in many scales.

Good point, but in my case, I used Woodland Scenic's risers & inclines. In retrospect, it would have been nice if they would have allowed for this by making the first & last section in each ramp half the incline of what the rest were. In other words, I used 2% ones; if the first piece & last piece were 1%, it would have helped a lot, especially for new users (and older users like me!). Then I also had the fatal error of having a couple of places where there were rail joints at or near the transition points. Again, having never done this, I didn't realize the problems until I started running test trains. I don't know what the proper measurements would be but I'd guess that a section of 36" flex track over a 1% transition to a 2% incline would have been about right.

To make matters worse, the vertical movement varies based on the particular locomotive. One that really gives me fits is an Atlas RS unit that seems to have a relatively short wheelbase and a little longer than usual overhang at the end. That really creates the vertical movement of the coupler. : (

Ain't this hobby fun??!?

dlm

Great story Roger; shows that experience triumphs over education.

Measurement error. :-) :-)

School + experience = education.

Absolutely right Wolf; my bad... I've had the school and 70 years of experience so should know better.

I'll buy that!

When I built my small 2x4 N-scale layout, I bought some foam risers and inclines from Woodland Scenics and experimented with the inclines.

On a 2x4 layout, the loco would barely pull itself up a one inch incline in that short of a distance. It couldn't maintain traction and would spin the wheels all the way up.To make matters worse, when it started down the incline, it was like watching a roller coaster.

I finally decided that half an inch was as good as it was going to get. The loco pulls it nicely and it doesn't have the roller coaster effect. It isn't much, but it at least gives variety to the terrain.

Thanks for the input. I'll experiment a little on the grade, but half inch seems like a good starting point. I'm going to try to go with a

30"x80" layout but have yet to find the plan I will go with.

OS

He was > the Montreal Terminal track supervisor for CPR.

Rog:

Excellent warning against overthinking the problem. According to an ancient book, MODEL RAILROAD ENGINEERING, which is full of neat if dubious little anecdotes (as well as a rare application of English- style MBS to model railroads) the usual way to lay out horizontal curves was to stake out the curve at intermittent points using Searles' easement tables, spike them to the ties, then smooth them out with repeated runs by 'a fairly heavy locomotive' before ballasting. Anybody care to confirm this as real late-30s practice?

Overthinking the problem...not uncommon in model railroading!

I suggest to the OP that he make a test track, and try running his engines up various grades. Spike down a minimum-radius oval, and tilt the board to see what happens. Make a long straight on a 2x4 and see what load they can pull at several different inclinations.

Cordially yours: Gerard P. President, the still-boxed-away Sparta Railroad

. . .

It's not too much of a problem at the bottom of the curve. As long as you allow the cork (or foam) roadbed to form it's own vertical curve you will not have the abrupt transition.

It is much more of a problem at the top of the riser. The riser ends with an abrupt angle. The only solution I have thought of is to trim a small amount off of the top of the last few riser sections and then stretch this section out about 1/3 more than its natural spacing. This should allow the cork roadbed to form a smooth curve over the transition.

Bill Dixon