Trains.com

Subscriber & Member Login

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

"Tipping on the Curve"

1674 views
7 replies
1 rating 2 rating 3 rating 4 rating 5 rating
  • Member since
    December 2001
  • From: Northern CA Bay Area
  • 4,387 posts
Posted by cuyama on Saturday, June 23, 2012 10:39 AM

By the way, the NMRA standard for car weight in N scale is .5 ounce plus .15 ounce for each inch of overall length of the car. If you have a particularly demanding combination of grades and curves, weighting beyond the NMRA standard may help.

Note also that poorly-rolling cars can exacerbate the tendency to stringline, as it's related to friction. So if the car-weighting is overdone, it could make matters worse if it causes the cars to roll poorly..

  • Member since
    December 2001
  • From: Northern CA Bay Area
  • 4,387 posts
Posted by cuyama on Saturday, June 23, 2012 10:30 AM

TrainsRMe1
Here's my question, I have my mainline running from my yard around a appox 35 in radius, into a  2% grade, 

Are you sure it's a 35" radius?  A couple of months ago you were talking about much tighter curves in N scale.
http://cs.trains.com/TRCCS/forums/t/204666.aspx 
http://cs.trains.com/TRCCS/forums/t/204778.aspx 

If you found more room and now have much broader curves, that's great. But the fact that the cars are derailing suggests that it's probably not actually 35" radius. Especially in N scale.

A 35" radius curve would be more than 6 feet across (diameter) with the benchwork. Is that what you have?

 If the cars are "stringlining", that is, derailing across the center of the curve, this is often the result of a steeply graded curve that is too tight, too steep, or has too abrupt of a change from level to grade, as others have noted. And the combination of those problems is especially bad.

Loaded double-stack models could be too light for their length, although many are heavy enough. The center of gravity is high, which exacerbates the tendency for stringlining.

Good luck.

Tags: Curve radius
  • Member since
    September 2004
  • From: Dearborn Station
  • 24,280 posts
Posted by richhotrain on Saturday, June 23, 2012 6:42 AM

There is a saying in the law: res ipsa loquitur.  The matter speaks for itself.

Either your grade is too steep on that curve, or the cars are too light and top heavy, or both.

Rich

Alton Junction

  • Member since
    August 2011
  • From: A Comfy Cave, New Zealand
  • 6,237 posts
Posted by "JaBear" on Saturday, June 23, 2012 6:32 AM

Gidday, if your other rolling stock is negotiating that curve O.K, from what I've seen, (not my modelling era), of those cars, they appear to be too light and too high.

One other thought though, is there one particular car starting the fall each time?

Cheers,the Bear. 

"One difference between pessimists and optimists is that while pessimists are more often right, optimists have far more fun."

  • Member since
    September 2003
  • From: Southeast Texas
  • 5,449 posts
Posted by mobilman44 on Saturday, June 23, 2012 6:21 AM

Hi!

I agree with all the preceeding posts, and may I add...........

Make sure your curve has a proper transition, AND the incline has a proper transition as well.   Sudden changes in trackage horizontally and/or vertically can mess up your train.

One other possibility is your train is too long/heavy for the weight and/or center of gravity of the cars.

 

ENJOY  !

 

Mobilman44

 

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

  • Member since
    August 2011
  • From: Perth, Western Australia
  • 226 posts
Posted by MonkeyBucket on Saturday, June 23, 2012 5:22 AM

The cars may be too light?

Cheers...

Chris from down under...

We're all here because we're not all there...

  • Member since
    February 2005
  • From: Vancouver Island, BC
  • 23,330 posts
Posted by selector on Saturday, June 23, 2012 1:59 AM

Do they tip toward the inside of the curve?   Is the grade just before the curve or at the end?  Where does the tipping take place in relation to the place where the curve and grade meet?

  • Member since
    December 2005
  • From: west of Portland Oreg.( the city of Roses
  • 599 posts
"Tipping on the Curve"
Posted by TrainsRMe1 on Saturday, June 23, 2012 1:09 AM

Hey Guys n Gals,

     Here's my question, I have my mainline running from my yard around a appox 35 in radius, into a  2% grade, for some reason, when I run my double stacks on that curve and grade, they tip over, my track is postioned fine, ( so I thought) what can be the problem???? that has me bugged!!!!

Subscriber & Member Login

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

Users Online

There are no community member online

Search the Community

ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT
Model Railroader Newsletter See all
Sign up for our FREE e-newsletter and get model railroad news in your inbox!