2.75% 75 ft grade (helix)

[jwar]

Having only a 11 x 15 ft room Im starting to build a 5 1/2 turn helix. I have noted on other threads that anything over 2% will burn out motors? I pull short trains about ten to fifteen cars account of limatations of lenght of sidings. I dont mind the lenght of time out of sight as I will be able to run three trains and work two swiching yards.
I orginaly thought my main problem was having two doorways to bridge, designed four trick swing downs.
If any of you have had prpblems with long steep grades I would like to hear about it. Thank you for your reply.

[cmrproducts]

jwar

I have a number of 4% grades and pull 12 car trains with a single engine and have had NO motor burnouts in 5+ years.

I really think some people say those things just to fire up those that have not been in model railroading long.

What happens is that the engine wheels will slip. To get around this just add (MU) another engine to the train.

I have added almost a pound of lead to an engine (specal cast weights) and had the engine pulling 25 car trains. And yes I burned out the motor but I had expected that this would happen but it took over 3 years to do it!

Bob H Clarion, PA

[cacole]

No, there's very little chance of burning out a motor by pulling a long grade. If this has ever happened to anyone, it was more a case of a bad motor to begin with than pulling a train up a grade, and it's even less likely to happen with a can motor than with the older technology open frame motors.

[ndbprr]

I don't think motor burn out is the issues at all. The problem is how do you determine how much a train has slowed down on the grade if it isn't visible? IF - note IF - it stalls on the hill and doesn't spin its wheels it will eventually burn out but the problem is how to regulate speed on a tough winding grade.

[jwar]

Thank you for the input as I started building the helix last night, your replays were very reasuring. The speed in the helix could be a problem and reminds me I have an old convex truck mirror (9inch) out in the garage that I may mount over the open helix, glad you gave me the idea.

Another concern was lenial expansion as it will be compleatly sodered. I"m leaving quite a bit of lenght between track nails to let the rail float a bit.

Thank you guys again and have a great day.

[Anonymous]

If you are running short trains, you might be fine. If you want to see how we built our model rr club's helix, with some hints about what to do, and what not to do check out.

http://siliconvalleylines.org/benchwork/helix.html

If you use threaded rod, you have the option of re-adjusting the grade in the future.

More stuff is also online @ http://siliconvalleylines.org/

-Dave Falkenburg
Silicon Valley Lines Model Railroad

[CP5415]

I have a couple of 4% grades on my layout & I plan on only running with 10 cars max basically due to siding length.
The only locomotives I have that's had a problem with pulling trains on these grades are my Proto RS11 & my Athearn RTR AC4400.
Everything else has had no problems with the trains assigned to them, so far!
I do have plans for helper units, when needed, so I won't have problems if & when any trains stall on a grade.

Gordon

[jwar]

Dear Dave
Wow.. your web site is very impressive as well being informative in other areas. Will have to look at the Sharks schedule and catch a double header. Your club is very professional and will visit.

Dear Gordon. Thanks, I dont think now i'll have any problems. however have the third loop compleated and found due to unexpected uncoupling. I may install really big cow catchers on the following extra or herhaps my next trip to the hobby shop...ill invest in a derreck amd crew cars.

Take care and thanks again..

[Anonymous]

The wheels slipping is a safety valve so you don't burn your motor. weight can be added if it doesn't cause too much current draw.

The curvature of the helix adds drag, witch combined with the grade determines how long of a train a given engine can pull.

George

[jfugate]

One thing to be aware of with a hidden helix is the drag affect of curve radius on model trains. John Allen did some research and came up with a table that shows the affects of various curve radii on grades.

I encountered this first hand on my HO Siskiyou Line. I installed a 24" radius helix with a 2.65% grade, thinking since it was hidden trackage I could go down to a 24" radius without issue.

WRONG!

The trains really lugged on that helix and my operating crews hated it. After talking with various folks on the Layout Design Special Interest Group forum, I realized from John Allen's formulas that my 24" radius curve would make the grade act more like a 4% grade ... yuck! All the visible grades on my layout were 2.5%, and now with this helix, I had the steepest grade (drag equivalent) on the railroad as *hidden* trackage.

Bad news. My crew and I decided the old helix had to go. We figured out a way to get a 40" radius helix in its place, with a 1.75% grade.

This made *all* the difference! The replacement helix operates like a dream, and has not given me one bit of problem, and that was the fall of 1994 when we tore out the old helix and replaced it with the new one.

It was a hard lesson to learn, but I'll never use tight radius curves on hidden trackage that's on a grade again. It's just asking for trouble.

[jwar]

Thanks Joe, your information is defently on target. I was looking at another post"equlevent grade" adds another 1.75 in radius resistence.

At this point I have the helex started and I have procrastenated on how to get a 20 inch elavation in a 11 x 15 room. My origanal plan was was with walkways and after seeing a few I decided an around the room layout is better, or at least for me.

So in the only corner that doesnt envolve a door is where it has to be and with a smaller radious then wanted inner 24 outer 25.5. I have all the plywood cut (free at a construction site, let me have the shortcuts) I will try it. I could go bigger radious.

Main reason I really into a helex is the keddie wye and the highway 70 bridge over oroville lake, which the tracks are under the hiway.

I sure value your advice and have allways enjoyed visiting your web site. Your road is very professional and if I can get mine within 50% of the siskys appearence, Ill be satisfied.