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!

over under help

456 views
8 replies
1 rating 2 rating 3 rating 4 rating 5 rating
  • Member since
    January 2020
  • 22 posts
over under help
Posted by wolf10851 on Thursday, January 23, 2020 2:21 PM

I am building a layout that is 5x11 in ho scale.  it has a 24" radius oval that has 2 turnouts to go to a 22" radius over under figure 8 for the incline I am trying to keep it at a 2% grade.  The issue that I am running into is that the last peice of the woodland sceenic incline is right at the crossover point under the top of the track and I am only able to go with a 3" rise which with the roadbed and locomotive I barely have enough room for the locomotive to pass under.  Does anyone have any suggestions on a better way to get more clearance?  if I go with a steeper incline then the locomotive will have trouble pulling cars up the incline correct?

  • Member since
    February 2005
  • From: Vancouver Island, BC
  • 21,919 posts
Posted by selector on Thursday, January 23, 2020 5:30 PM

Congratulations!  Your new learning and discoveries are oh-soooo-typical for people putting together their first layout. 

Yes, your locomotives 'may' struggle quite a bit to get up steep grades, but you can set up a grade on a board, set a certain steepness, and then run a trial.  You'll learn what your locomotive can pull at a given grade, and it will be as close to empirical evidence as one can get.  From there, you decide what compromises you'll have to make to get what you want, including redesigning the entire concept (yes, many have had to do that).

There's a trick with a figure eight.  Your climbing track, the one overhead, needn't do all the clearance-making.  Instead, have your lower track, the one that passes below the top track, descend a bit and then climb again on the other side of the overpass.  Yuh gotta do what yuh gotta do if you want to keep your space and track configuration the way you'd like it to be.

When figuring out the height you'll need for clearances, don't forget to include the depth of the bridge/overpass below the ties and rails.  It matters!!

  • Member since
    December 2015
  • 6,373 posts
Posted by BigDaddy on Thursday, January 23, 2020 6:01 PM

There is a forumula proposed by John Allen that the effective grade increases on curves by 32/R    or 32/22= 1.45%   So your 2% grade is really 3.45%

Small locos will have a problem.  Double heading helps and some feel that is not a bad way to go.

selector
have your lower track, the one that passes below the top track, descend a bit and then climb again on the other side of the overpass.

A good idea but if you are building on a flat surface, plywood or foam, and using WS foam risers, they only go up.

Henry

COB Potomac & Northern

By the Chesapeake Bay

  • Member since
    September 2014
  • From: 10,430’ (3,179 m)
  • 1,121 posts
Posted by jjdamnit on Thursday, January 23, 2020 6:18 PM

Hello All,

Welcome Welcome

A few words of general advice...

Building any pike you will need some specialty tools. My go-to source is Micro-Mark.

If you are building overhead trackage I also recommend getting a National Model Railroad Association (NMRA) track gage.

If you are an NMRA member they are only $5.00 +S/H through them. Micro-Mark offers one for $19.95 +S/H.

This gage will help you determine the minimum recommended overhead track clearance, according to NMRA standards and recommended practices

Yes, you can...

selector
Instead, have your lower track, the one that passes below the top track, descend a bit and then climb again on the other side of the overpass.

But that depends on the makeup of your sub roadbed. If you are using a foam base then you can carve out the decline under the overpass.

If you are not using a foam base this can be more difficult, depending on the material.

What are you using to build your overpass?

Are you using a Woodland Scenics incline/decline set, a concrete or wooden trestle pier set or fabricating it on your own?

You did not mention if you are running primarily steam or diesel motive power.

If you use a 3% incline/decline consider adding another locomotive to help in pulling power up the slope; AKA "Doubble Heading".

Another option would be to run fewer cars up the slope.

Hope this helps.

"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"

  • Member since
    January 2020
  • 22 posts
Posted by wolf10851 on Friday, January 24, 2020 3:03 AM

First off thanks so far for the advice given.  I am running strictly Diesel GP9 and SD45 I also have an ac6000 that may run on the over under.  For the layout I am running a 1 inch foam bed but then plywood underneath, so technically I do have 1" to play with in carving down to go under then trestle, but I would rather not if I can help it because I was thinking of throwing a stream in there.  for building the incline yes I am using WS incline set and as mentioned before they really just go up not up and down.  There was also the suggestion of running a shorter train but I really like the look of a 15 to 20 car train (I am hoping that I can pull that up the incline)  As for consisting the loco I think it would look a little funny an SD40-2 and a GP9 in consist...........yes I know I am being picky and making this difficult :(

  • Member since
    July 2006
  • From: west coast
  • 4,897 posts
Posted by rrebell on Friday, January 24, 2020 10:24 AM

Got a similar problem. Fiqured out if I ditched the cork just at the overpass and ran a peice of metal under the flex track, I could pick up the needed clearance to maintain a 2% grade.

  • Member since
    February 2005
  • From: Vancouver Island, BC
  • 21,919 posts
Posted by selector on Friday, January 24, 2020 11:10 AM

BigDaddy

There is a forumula proposed by John Allen that the effective grade increases on curves by 32/R    or 32/22= 1.45%   So your 2% grade is really 3.45%

Small locos will have a problem.  Double heading helps and some feel that is not a bad way to go.

 

 
selector
have your lower track, the one that passes below the top track, descend a bit and then climb again on the other side of the overpass.

 

A good idea but if you are building on a flat surface, plywood or foam, and using WS foam risers, they only go up.

 

 

Understood, which is why I added that he might be better of reconsidering his entire approach to the track system. If he'd like to investigate what that means, or what alternatives he could explore, we could take him there.

  • Member since
    February 2005
  • From: Vancouver Island, BC
  • 21,919 posts
Posted by selector on Friday, January 24, 2020 11:15 AM

wolf10851

... technically I do have 1" to play with in carving down to go under then trestle, but I would rather not if I can help it because I was thinking of throwing a stream in there...

 

A stream is unlikely to be found carved through flat land.  They DO at times, but not very often.  A stream is more likely to have carved out a depression which the trestle will cross. 

Could you add another layer of foam?  That will give you more relief space to carve.

You'll get to run that longer train you're hankering to see run on your layout if you do the work to make it a reality.  Constructing a pleasing layout is not quick, and generally not easy.  It takes forethought, and it takes flexibility when you encounter obstacles to your vision that reality and learning place before you.

  • Member since
    January 2020
  • 22 posts
Posted by wolf10851 on Saturday, January 25, 2020 2:49 AM

selector
I am Always open to suggestions especially when doing something like this.  I do not have my heart set on the over under.  My likings would be something that I could run 2 seperate trains on (or more if possible), minimum radius is 22"and I would like to take up as much of the 5x11 platform as possible.  I also want something a little more interesting that just an oval inside an oval

 

 
BigDaddy

There is a forumula proposed by John Allen that the effective grade increases on curves by 32/R    or 32/22= 1.45%   So your 2% grade is really 3.45%

Small locos will have a problem.  Double heading helps and some feel that is not a bad way to go.

 

 
selector
have your lower track, the one that passes below the top track, descend a bit and then climb again on the other side of the overpass.

 

A good idea but if you are building on a flat surface, plywood or foam, and using WS foam risers, they only go up.

 

 

 

 

Understood, which is why I added that he might be better of reconsidering his entire approach to the track system. If he'd like to investigate what that means, or what alternatives he could explore, we could take him there.

 

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!