Trains.com

Reverse curve

7016 views
38 replies
1 rating 2 rating 3 rating 4 rating 5 rating
  • Member since
    December 2017
  • 2,671 posts
Posted by Lithonia Operator on Sunday, February 5, 2023 4:19 PM

Thank you, gents.

 

Still in training.


  • Member since
    December 2006
  • 1,754 posts
Posted by diningcar on Sunday, February 5, 2023 3:48 PM

rcdrye, you are correct.

I believe Santa Fe used 570 foot spirals with a gradual step up to three and a half inches of super elevation. But the 500 feet of intervening tangent still applied. 

  • Member since
    May 2012
  • 5,017 posts
Posted by rcdrye on Sunday, February 5, 2023 2:12 PM

Superelevation follows the "spiral easement" entering or exiting a curve.   The tangent between curve allows the center lines of equipment to line up straight before starting a new curve.

  • Member since
    January 2019
  • 1,686 posts
Posted by Erik_Mag on Sunday, February 5, 2023 1:46 PM

Would one of the reasons for needing 500 feet of tangent be dealing with transitioning superelevation? For model railroads where track isn't canted, allowing for the length of the longest car should be enough.

  • Member since
    December 2006
  • 1,754 posts
Posted by diningcar on Sunday, February 5, 2023 8:21 AM

The sharper the curve in degrees the greater the distance needed. Also, the speed which trains operate is involved.

BNSF (former Santa Fe) constructed a new line through the mountains of Arizona in 1959-1960 which allowed passenger trains to operate at 90 MPH. and had one degree (or less) curves. The minimum distance between curves was 500 feet of tangent. 

 

  • Member since
    December 2001
  • From: Northern New York
  • 25,020 posts
Posted by tree68 on Saturday, February 4, 2023 4:36 PM

ChuckCobleigh
I new you'd go off on a tangent, there.

You know MC - always on the straight and narrow...

LarryWhistling
Resident Microferroequinologist (at least at my house) 
Everyone goes home; Safety begins with you
My Opinion. Standard Disclaimers Apply. No Expiration Date
Come ride the rails with me!
There's one thing about humility - the moment you think you've got it, you've lost it...

  • Member since
    December 2001
  • From: Sunny (mostly) San Diego
  • 1,920 posts
Posted by ChuckCobleigh on Saturday, February 4, 2023 3:49 PM

mudchicken

IF you don't have several hundred feet between those curves turning in opposite directions, you have a potential nightmare on your hands.

I new you'd go off on a tangent, there.Whistling

  • Member since
    December 2001
  • From: Denver / La Junta
  • 10,820 posts
Posted by mudchicken on Saturday, February 4, 2023 9:06 AM

IF you don't have several hundred feet between those curves turning in opposite directions, you have a potential nightmare on your hands.

Mudchicken Nothing is worth taking the risk of losing a life over. Come home tonight in the same condition that you left home this morning in. Safety begins with ME.... cinscocom-west
  • Member since
    July 2016
  • 2,631 posts
Posted by Backshop on Wednesday, February 1, 2023 7:05 AM

I believe it's the same thing as an S-curve.  Where it starts going in one direction and then goes in the opposite.

PS--I just typed "railroad reverse curve" into Google and that's what it is.

  • Member since
    December 2017
  • 2,671 posts
Reverse curve
Posted by Lithonia Operator on Wednesday, February 1, 2023 12:53 AM

I've seen term "reverse curve." What does that mean?

Still in training.


Join our Community!

Our community is FREE to join. To participate you must either login or register for an account.

Search the Community

Newsletter Sign-Up

By signing up you may also receive occasional reader surveys and special offers from Trains magazine.Please view our privacy policy