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Outside radius has more drag on train.

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  • From: Northern Ca
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Outside radius has more drag on train.
Posted by jwar on Saturday, October 23, 2004 11:39 PM
Using a double helix with a 23 and 25.5 radius. The 3/4 ply has no warps, no cups, and perfectly flat. The grade is consistent to a very accurate bubble level (Machinist set up level).

Theroreticaly the outer dia should have a smaller percent of grade as its longer in lenght per circle of the helix.
Outer track is a 2.77 percent, inner is 2.50 with an 4 in rail to rail rise. Perhaps the curvature drag is another 1. 5 or so added to the grade. ( I cant find the thread about the curviture resistence, was posted a few weeks ago and very interesting)

So the question is, why would the same engine pulling the same 18 cars in exact order pull the inner track at a lesser throttle setting, then pull the outer loosing speed and getting wheel slip.

Both tracks are clean and wiped with alcohol.

Anyhow Im very pleased with this new helix, There has to be a reason.


John Warren's, Feather River Route WP and SP in HO
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Posted by cacole on Sunday, October 24, 2004 12:54 PM
My guess is, with everything else being equal, that the outer radius is a longer run of track than the inner radius, and thus the train is travelling a further distance on the outer track.
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Posted by dragenrider on Sunday, October 24, 2004 5:33 PM
This is a wild guess, but could it be because the engine's wheels put more pressure on the outside rail on the tighter curve? On the outside track the trucks aren't turned so tight and there is less pressure on the outside rail compared to the inner curve.

The Cedar Branch & Western--The Hillbilly Line!

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Posted by jwar on Sunday, October 24, 2004 9:06 PM
you both may be right. But the helix works better then I thought it would. So...as the saying goes...If it aint broke...dont fix it.

Was doing this as a test on the new track. I cant run more then 12 cars due to siding lenghts anyhow.
John Warren's, Feather River Route WP and SP in HO
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Posted by Anonymous on Sunday, October 24, 2004 11:03 PM
Two possibilities come to mind. First , is there an electrical problem reducing the power to the outer track? Or, is there an area of the outer track where the rails are sllghtly binding the wheels, just enough to offer some friction but not enough to stop or derail the cars?

I think you're right; there must be a reason. The fun part is finding it. [:)]

Wayne
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Posted by Anonymous on Monday, October 25, 2004 8:33 AM
Might think of this way, you have posi-tract rear end, when going around a corner the outside wheel is getting dragged around it. Because it has a longe arc to travel, compared to the inside wheel.

Just a thought.....

Ryan
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Posted by dknelson on Tuesday, October 26, 2004 8:26 AM
This is a wild guess -- but the inner curve, the tighter radius, presumably has a slightly tighter gauge which in turn might involve the flanges gripping the rail better and actually giving better traction even though the drag is also greater. Have you checked the gauge of the rail?
Dave Nelson
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Posted by jwar on Tuesday, October 26, 2004 6:38 PM
Boy O Boy I sure feel stupid over this one. Found the problem.
After finishing my helix and grabbing a cup of coffee in the kitchen. I asked my wife if she would like to watch the first test train going up the helix.

As we entered the train room she wanted to get inside the helix and look at it. She always drags her fingers loking for dirty track, and stated "Wow your track is really clean". Watch this Honey, as I started the trains maiden voyage. Pulled the inner loop great and backed down. Put the engine on the other end of the train and ran her around the room and up the outer loop, It lost traction.
Last night I overheard her laughting on the phone with my daughter, all I heard was, "Its driving him nuts and Im not going to tell him I had hand loton on my hands. So at this time she has no clue I know......

This all started when she asked me what a cornfield meet was.
after brousing a MR mag. I told her it was about the same as when she backs the car out of the driveway. she asked "What" Then I replied, A confield meet is two trains crashing head on at 180 degrees ........ yours are at 90.
My apologies to the above for thier time.
John Warren's, Feather River Route WP and SP in HO
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Posted by Anonymous on Tuesday, October 26, 2004 10:09 PM
Hee,hee! I knew it was the track, but never suspected it was wife-related!

Told you the fun part of a problem is finding the reason. Good sluthing! [:D]

Wayne
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Posted by dknelson on Wednesday, October 27, 2004 5:23 PM
Hmm sabotage by spouse?
The only way to properly retaliate .... go buy yourself something nice for the layout.
Dave Nelson
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Posted by Pennsy58 on Wednesday, October 27, 2004 6:46 PM
Now what, We all need to install a hand washing station next to the entrance to our prized layout? Throw a Kadee # 5 in her bowl of soup, see how she likes it!!! Hee Hee
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Posted by jwar on Wednesday, October 27, 2004 8:51 PM
Best ideas on this forum yet...HmmmmmmI wont do the Kadee, enjoy sleeping indoors and hot meals (Im kind of old and spoiled) but I could get away with picking up a pair of Broadway F units...I can see it now...Hey Honey come in the train room I think I found the solution....Yeah thatal work...
You guys have a great day...John
John Warren's, Feather River Route WP and SP in HO
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Posted by Anonymous on Wednesday, October 27, 2004 10:57 PM
Haha she sure got you. But remember.....Revenge is sweet.

Benjamin R.
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Posted by cacole on Thursday, October 28, 2004 11:26 AM
Okay, so now we all know that hand lotion can't be used as a track cleaner.

Has anyone ever tried Simple Green? I'm about to give up on Goo Gone from what I keep reading about it leaving a sticky film on the rail. The best solution I have found so far is Maas or Magic Wadding Polish, but these are labor intensive and must be applied by hand. For a 20x40 foot HO scale layout, we need something that can be used in a Centerline track cleaning car. A lot of people recommend 98 percent rubbing alcohol, but doesn't it evaporate too fast to use for a Centerline car?
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Posted by Anonymous on Thursday, October 28, 2004 4:17 PM
That's too funny!!! I am glad to see though that your wife takes an interest in your hobby. The fact that she can joke with you and your daughter about it says alot. Of course since you weren't supposed to know - I think you need to fix that traction problem the prototypical way. Helper engines. Go get yourself a couple of Kato SD's to help your trains up the track!
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Posted by mcouvillion on Friday, October 29, 2004 12:40 PM
My first thought is that you have fewer track feeders per x feet of track on the outside loop than on the inside. This will result in more voltage drop through the rail, and less voltage to the motor in the engine. Consider a track feeder at 3-4 foot intervals on the loop, not parallel to those of the adjacent loop. You also want to feed power to each section of flex track and don't rely on rail joiners to carry power from one section to another. Rail joiners are for track alignment - ONLY! Drop feeders to each section of rail and you won't have power problems.

Mark C.
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Posted by Anonymous on Friday, October 29, 2004 1:26 PM
lol
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Posted by dragenrider on Friday, October 29, 2004 6:19 PM
That's great! [(-D] What a wife!

The Cedar Branch & Western--The Hillbilly Line!

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Posted by bogp40 on Friday, October 29, 2004 8:03 PM
What was it you wanted in Overland Brass?

Modeling B&O- Chessie  Bob K.  www.ssmrc.org

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