# Throwing me a curve

Discussion in 'FAQs' started by Pitchwife, Feb 24, 2003.

1. ### WoodieActive Member

Clark,
I have (well had ) an incline beginning on a curve. I didn't have any probs, however, the "strain" on the locos (if I can call it that), is maybe added together. The strain of pulling round the curve, combined with the strain on the incline, so maybe, if you can, lessen the incline on the curve to compensate, maybe?
I found the capacity of the loco to pull a load up an incline, while on a curve to be greatly reduced, compared to similar grade of incline on a straight piece of track.
2. ### PitchwifeDreamer

That's kind of what I thought. The attached image is one way that I thought of creating the proper easment, I just didn't know what to call it. The drawing is prety crude, but it should give you an idea of what I had in mind.

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3. ### jcv13New Member

easements

Just a thought or two to add to those already mentioned. I have used the math maintain a 3% or less grade and I have eyeballed it. Your grade and radius considerations need to also include the length of rolling stock and motive power being used. Longer equipment has more friction or drag on curves! Just a thought. This is my first post on this site and I am glad to join you all!!!!
4. ### RailRonActive Member

Welcome aboard jcv!

You got an important point here. There's an old rule: The longer the cars, the bigger the radius of the curves. Mostly it is only meant for aesthetical reasons - long passenger cars on tight curves look ridiculous. But yes, the friction increases, too, as the cars are also pulled 'sideways' through a curve. And this lateral friction acts as a brake for the train.

When the curve is on a grade, the effect can be even stronger. Suddenly your fine loco pulls only four instead of ten cars! Like Woodie said, compensating a curve by lessening the grade is a good idea (IF you have room enough on your layout).

Here's a pic to illustrate my earlier post concerning vertical easements. The roadbed will adjust itself in the 'vertical curve', so there is no need to add many supports there.

A similar rule as above applies here: The longer the wheelbase of your longest rigid frame steam loco is, the longer the easement should be drawn out. Otherwise the middle drivers are hanging in the air, and then you have real problems - both with traction loss and with derailments!

Ron

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5. ### ClerkActive Member

Hopefully you can make out the easement in this photo of the grade. Right at the beginning, I dug out the foam so the plywood fit right in even with the table. The grade gradually raises up about 1/4 inches in 20 inches. then up to about 2.5 degree raise. That section is 11 feet long and the end of the track is 3 1/2 inches high from ground zero.

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