Turnout dimensions

[Ingeniero1]

I’ve been away from model railroading for 13 years, and I designed my last layout about 20 years ago, before I had any CAD programs. I am now returning to MRR, and want to design a layout using DesignCAD, which is what I have been using for about 20 years, since it was called ProDesign.

 Anyway, where can I get specific HO-scale turnout dimensions so I can accurately layout my yards, spurs, sidings, etc.? I am thinking primarily on No. 6’s for the main and No. 4’s for the yards, but I may instead go with No. 8’s and No. 6’s if I find a good source.

 BTW, all I have left is some code 83 flex track as far as track is concerned. I do have all my rolling stock and engines, and most of my buildings, and I plan to use DCC, probably Digitrax.

 

Thanks!

Alex

 

[Modeloldtimer]

You can always go to the The National Railroad Associations web site for imfomation on Model Railroading.
Here's a link to the Turnout Dimentions.
http://www.nmra.org/standards/rp12_3.html
Hope this helps.

[GGOOLER]

Alex

If you know you are going to build a layout, go out and buy the turnout and do some measuring.

Thats what I did since im a long time AutoCad user. and for the most part i just draw the center lines of track and turnouts.

hope this helps

Glenn

[Anonymous]

I also use AutoCAD and measured and laid out the dimensionsfor several different manufacturers TOs.  Somewhere I found dimensions for #6 & #8 TOs that workedvery well on some handlaid TOsI got them off of the internet, but I do not recollect the address

[fwright]

 Anyway, where can I get specific HO-scale turnout dimensions so I can accurately layout my yards, spurs, sidings, etc.? I am thinking primarily on No. 6’s for the main and No. 4’s for the yards, but I may instead go with No. 8’s and No. 6’s if I find a good source.

  

Thanks!

Alex

 

Alex

 

Unfortunately, very few commercially made turnouts follow the NMRA table dimensions very closely.  For instance, an Atlas Custom-Line #4 turnout is really about a #4.5 frog angle with a closure rail radius of about 22".  Shinohara turnouts tend to be longer and have wider closure radius than NMRA dimensions for a given frog angle.  So unless you use an existing model railroad-specific CAD program with libraries for commercial turnouts already loaded, you will have to measure the desired turnouts and build your own library.

 

For this reason, and because I'm lazy, I use the free Atlas RTS software to lay out the critical areas - yard ladders, multiple turnouts and crossings, curves of more than 90 degrees, etc.  I usually don't bother connecting these critical areas with the software because the time isn't worth it.  I print the plan and sketch in the missing links.  Since I usually handlay my track, I know I can fit inside the space the Atlas components require.  That's really all my computer plan is -  a series of checks to see if I can accomplish what I want in the space available.

 

1) I check to see if siding, yard track, drill track, and staging track lengths are compatible with my intended train length.  I also check to see if there is at least 1.5 train lengths between passing sidings on the main line.

 

2) I perform rough grade calculations based on no switching moves of any kind on a grade (can't leave parts of trains standing on more than a 0.75% grade) to see if the grades are within my standards.  I check to ensure there is normally at least 2" (in HO/HOn3) plus an inch for evey inch of difference in elevation between roughly parallel tracks (gives 45 degree scenery).  Anything less is going to require a special scenic treatment.

 

3) I use the structure library in the software to lay out some typical sample structures for a fit check.  I check for horizontal clearance with other track and reasonable steepness of hillsides under and around structures.

 

4) Finally, I check for operations.  Do spurs have the right capacity in car lengths?  Are switchback tail tracks long enough?  Do all my spurs face the same way?  I run some sample trains in my mind, and sort through the moves require to do the tasks that the operational scheme requires.  Does each track make sense?

 

5) Submit the plan for review on this or other forums.  Just like proof-reading, others will spot things I have missed.  I have to remember that others are volunteering their time to analyze my plan, and thank them, even if I decide not to take or don't like their suggestions.

 

After these checks, the plan is a general guide regardless of whether one uses handlaid or commercial track.  The number of MRs I have heard of building their layout exactly as designed by any CAD software can be counted on less than 2 fingers.  If using commercial track, lay the turnouts out full size and go from there.  Chances are very good they will not fit exactly as planned!

 

The above is based on the assumption that you already have your operational scheme, prototype, era, equipment, and other givens and druthers already established.

 

my thoughts, your choices

Fred W

[Renegade1c]

there is a free program called xtrkcad. This program has many of the commercially availible turnouts already done and is very powerfull program. Like I said it is free. It does have a bit of a learning curve but it is not too difficult. This is what i used. Otherwise I would say that you would probably have to go buy some and measure them.