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Yard mouth on downgrade?

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  • Member since
    January 2009
  • 44 posts
Yard mouth on downgrade?
Posted by sverk on Monday, December 6, 2010 6:06 PM

Planning my layout, I came to think derailments are more likely to happen when a string of cars is being pushed than when pulled, right?  I figure this is because when pushing, especially through curves, the coulpers on adjacent cars often get more out of alignment with each other, and more of the pushing force will act sideways.

So, would it be useful to put the switches that will make up my yard mouth (a double-slip, a 3-way lap, and a few regular switches) on a slight downgrade, and that way reduce the pushing forces between cars?
(It is a stub ended yard).

Would that be a good idea?

 

  • Member since
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  • From: Southeast Texas
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Posted by mobilman44 on Monday, December 6, 2010 6:19 PM

Hi!

Your thoughts on the tendency to have more derailments when a string of cars is pushed, rather than pulled is probably right - at least for my experiences in HO and O (years ago).

That being said, a well thought out plan and quality trackage put together properly (i.e. easements for curves, no reverse curves without a decent tangent track in between, etc., etc.) should be able to easily handle "whatever" on a flat surface. 

While a slight downgrade may help things go smooth (it shouldn't matter on good trackage), it will also hinder you from spotting cars on that grade. 

Right now I'm dealing with a caboose track that I thought was level, but it is not.  With Intermountain wheelsets, nothing stays put.  So I'm dealing with this problem, which you could easily have as well.

By the way, the more planning you do - using scale drawings and "no cheating" - will reward you through the rest of the layout's life.

ENJOY  !

 

Mobilman44

 

Living in southeast Texas, formerly modeling the "postwar" Santa Fe and Illinois Central 

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  • From: Central Vermont
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Posted by cowman on Monday, December 6, 2010 10:27 PM

Mobileman44

A suggestion to hold your cabeese in place.  Take a very thin piece of piano wire, stick it into and through the roadbed.  Cut it off just above axle level.  I have heard  of folks doing this on single spots for cars, no reason you couldn't have several along the track.  The wire will give enough to let a loco pull or push the car over it, but is stiff enough to keep it from rolling on its own.  A thin wire shouldn't be too visable.

Good luck,

  • Member since
    February 2005
  • From: Vancouver Island, BC
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Posted by selector on Tuesday, December 7, 2010 2:26 AM

Even a smallish clump of tuft grass from Woodland Scenics should work for this purpose.  Place maybe six or eight strands in a clump in the middle of the tracks and that should hold one or two cars on a moderate grade.  Add more fibers as needed.

Crandell

  • Member since
    September 2003
  • From: Southeast Texas
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Posted by mobilman44 on Tuesday, December 7, 2010 7:17 AM

To the folks that addressed my caboose track incline.........

  Thanks for the suggestions!  On that subject, I recently read "somewhere" where a fellow put a KD spring at the end of one axle.  He maintained that did the trick but didn't really affect the rollability.

I've got a slew of ATSF cabeese (got inspired by Mr. Sperandeo's MR article years ago).  As my problem is only with the caboose track, at least I've only got 12 or so cars to play with.  I do like your ideas as well, and may experiment with each.

The obvious solution is to relay the track, but it is intricately tied into the mains and various crossovers, and I don't want to pull them all up. 

ENJOY  !

 

Mobilman44

 

Living in southeast Texas, formerly modeling the "postwar" Santa Fe and Illinois Central 

  • Member since
    November 2008
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Posted by grizlump9 on Tuesday, December 7, 2010 8:26 AM

a slight downgrade for your yard lead and ladder tracks is not only a good idea for operating dependability but it is also quite prototypical.

  the last two layouts i built had rather large classification yards (for HO scale, at least) and both had the yard lead and ladder tracks on a 1/2-3/4% downgrade.  this resulted in near zero derailments, even when shoving 35 or more cars.

if the grade continues a ways into the individual tracks, you will notice some of the cars will keep rolling on into the clear after you cut them off (i have kadee magnets for uncoupling).  some of the late P2K cars have such free rolling trucks, they are unbelievable.  a good sneeze will send them to the other end of the yard.

  only downside to this is your yard engine will have to be a good puller to handle a long track full of cars when you pull them up the lead to begin switching or to set them over to another track.  that is why we rotate an atlas geep out of the road pool for the drill job most of the time.

 

grizlump

  • Member since
    January 2009
  • 44 posts
Posted by sverk on Tuesday, December 7, 2010 6:01 PM

Thanks for all the responses!

It makes me convinced that I will put the yard mouth on say 0.5 deg downgrade.
I realize also that I need to be careful to avoid bad vertical curves, thus I will have to start the grade gradually and clearly in advance of the first switch, and to level out only slowly beyond the switches.
Shouldn't be all that difficult with just a half-degree grade.
All the switches in the same plane -- just slightly tilted.

Tufts of grass to keep cabeese in place may also come handy,

Thanks!

  • Member since
    August 2006
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Posted by trainnut1250 on Wednesday, December 8, 2010 1:33 PM

For the contrarian view:  Skip the grade.  The gain you will get from the grade is not as important as the gain you will get from impeccable track work and careful design and execution.  Switching on a grade is a pain.  You Are always having to deal with roll aways - etc.. 

Building the yard on the grade is IMHO an unnecessary complication for little operational benefit.  Take the time you will spend setting up the grade and spend it on the trackwork and switch tuning.  I regularly operate on several layouts - no one has a grade in the yard.  We have near zero derailments (other than operator error).

Your mileage may vary,

Guy

see stuff at: the Willoughby Line Site

  • Member since
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  • From: Muskoka, Ont.
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Posted by BigG on Wednesday, December 8, 2010 10:28 PM

Mobilman44

  Take a look at  November 2001 Model Railroader, page 109.

There's an article by Andy Sperandeo on using a Tortoise and linkage to fix just what you are having trouble with.

 It was recommended to me on this forum to hold a train in place on a grade, while the loco is disconnected to switch a car onto a siding. I built it and it works beautifully.

  Have fun,    George

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