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Double main line track spacing & Tourtoise switch machine use

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  • Member since
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Double main line track spacing & Tourtoise switch machine use
Posted by Coastie71 on Sunday, February 2, 2020 2:15 PM

I'm new to the hobby having only built a crude N scale 4x8 in late 80s.  Now that I'm retired and settled down I'm designing an HO DCC layout 18' x 24' double main line basically in an E shape with a middle island.  I want to be able to run diesel only freight and full length passenger cars from the 1960s thru 80s.  I've read up on some previous posts as well as NMRA specs, but still not sure how wide to make the curve tracks so that two passing full length passenger trains will not hit each other.  Right now I'm planning on 30" radius outer and 27.25" inner track for the curves and probably 2 1/6" spacing for straight/tangent track.  I don't own any rolling stock or track yet so I can't test it out until right before I build, but currently trying to make sure that what I design will or should work.  I know the NMRA dose'nt recommend anything below 32" radius 2 1/2" spacing, I assume, inner track for longer cars, but I'm thinking if I increase the spacing an extra 1/4 inch I might be safe.  Don't want to go with the larger radius if possible as I find it doesn't allow me to have enough straight areas for turnouts, bridges, etc.  Also want to make sure that purchased double tunnel portals and bridges will work with this or whatever the recommended spacing should be for it to work.  I have not been able to find any information on double bridges to indicate what the track spacing should be.  Going to use Atlas code 83 flex track throughout and number 6 and 8 turnouts.  I'm using the Atlas track planning software to design.

 

Not sure if this is the right forum for discussing tourtoise switch machines, but having read many DCC corner articles I have a hard time understanding if these are the only switches or electrical/electronic devices I need for turnouts to avoid shorts, stalls, etc.  I will only have turnouts for small yard and for branches off the main for industries, etc.  I'm not going to have crossovers or wyes, just track that will return to the main either from the same turnout or a turnout further down on the same main track.

Thanks for anyone's help!

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Posted by BigDaddy on Tuesday, February 4, 2020 7:57 PM

Welcome to the forum.  The way your initial moderation works is that you posts appear after you post, sometimes much later, but they are couple pages down in the list of latest posts.

I think your first question might be answered in John Armstrongs track planning for realistic operation, but I don't have my copy available at the moment so I will pass.

Tortoise  these are turnout motors.  You need a way to control them. Addressing switches by DCC controler is cumbersome, so you will probably want a physical switch.  The tortoise itself has a couple built in switches.  The built in switches can trigger signals, or LED's on your control panel or power the frog of the turnout. 

Powering frogs is a little bit controversial.  It's never a bad thing, but some argue it is not needed for long wheel base locos.  Of course some frogs are longer than others, the atlas curved turnouts are but one example.  There are other ways to power frogs, frog juicers, caboose ground throws that have a 'switch'  and some people use a switch physically connnected to the throw bar to both move the points and power the frog.

Henry

COB Potomac & Northern

By the Chesapeake Bay

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Posted by ATLANTIC CENTRAL on Tuesday, February 4, 2020 8:20 PM

Coastie, Welcome.

I will be right to the point, use bigger curves if you can, you will be happy latter.

I would not use less than 36"R for full length passenger cars.

Spacing, 2" on striaghts. On curves the larger the radius, the less you have to space them out. At 36"R the NMRA recommends about 2-1/2" centers. I have never found that much of an increase necessary at 36"R, but I model the 50's, so while I do have long passenger cars, I don't have large/long freight cars.

Sheldon

 

    

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Posted by Coastie71 on Wednesday, February 5, 2020 1:59 PM

Henry/Big Daddy, thanks for the reply and the welcome.  I think I understand what your saying to an extent and that I might need to use frog juicers since I'll have several Atlas curve turnouts, but as you indicate I might be able to power the frog using the Tortoise turnout motors.  I forgot to mention, I think, that I will not have any reverse loops also (if I understand properly that that is a track that returns to the same turnout from the other direction), just sidings and small yard so I just want to be able to return to the same main track either by backing out or return at another turnout.  I think I'll go with the physical switches like you mention, kind-of-like what I did with the 1980's DC N scale railroad I built that had a board with a whole bunch of switches, only thing is the turnouts or the switches or both didn't work a lotta times.  I'm assuming things have gotten alot better since then.

Finally I plan on getting the John Armstrong book you mention.  I know I have alot more reading I need to do before I start the building phase.  One last question, should I use the DCC forum to ask wiring and DCC related questions or is it OK to talk about them here?

Thanks again, Gary (Coastie71)

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Posted by Coastie71 on Wednesday, February 5, 2020 3:28 PM

Sheldon, thanks for the reply and information and I totally agree with you about the larger radius.  However, I tried to create a track plan that had 30"R inner and 32.5"R outer curves, but to keep that radius throughout it made my inner double main line constant curves almost to the point where the inner main line approached the outer main line track on my 3 1/2' wide areas and only a couple of areas where I could get some straight track to work and that's with 3 1/2' wide lengths on the top and bottom of the E shape plan and 4' at the main end and 6 1/2' by 8' wide at the ends of the top and bottom of the E and 6 1/2' wide at the middle peninsula.  Even with these dimensions my aisles are limited to 2 1/2' and 2' entering the layout. That made trying to have any double wide bridges to work and even caused problems with turnouts, yard location, etc.  I was reading the NMRA S-8 Standards where they mention 2 1/2" minimum spacing for 32"R and your recommended 36'R (again I'm assuming that is for the inner track), but I read one forum person who said they were able to use 2 1/4" spacing with 30"R (again I assume inner curve) and run full lenght cars/locos.

I could change my plan to eliminate the middle peninsula and just have very wide areas for the curve turn arounds so if I use 36'R for the inner curve I'm assuming that means I would need to have benchwork to be at least 7+' x 9+' wide to avoid running the track right to the end of the benchwork.   I could do this, but this will also decrease my mainline run significantly and not sure how it would work for yards, etc.  I'll give it a try, but maybe I'm going to have to give up on the idea of running longer cars and stick with normal length freight train cars only.

Again, I appreciate your help and maybe I'll be able to work a plan for the larger radius.

Thanks, Gary (Coastie71)

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Posted by RR_Mel on Wednesday, February 5, 2020 4:50 PM

Welcome
If you are planning to use commercial double crossovers I also say to go with 2” centers for straight track.  The commercial double crossovers are 2”, a double crossover was the first piece of track laid on my layout.
 
My minimum mainline radius is 28” and 85’ cars have a lot of overhang.  I ended up going with 72’ passenger cars, very little overhang on 28” radius.
 
 
 
 
Mel
 
 
 
My Model Railroad   
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
 
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Posted by BigDaddy on Wednesday, February 5, 2020 5:29 PM

Coastie71
One last question, should I use the DCC forum to ask wiring and DCC related questions or is it OK to talk about them here?

Management would prefer all electrical things in the 'Lectric Forum.

This is a useful page https://dccwiki.com/Wire_Sizes_and_Spacing

As is http://www.wiringfordcc.com/   In my opinion he over emphasizes tail light circuit breakers.  Kalmbach has some good introductory books on DCC, though I as a newbie, when I read them, I thought I would need 4-5 boosters.  If you build an empire, you might, but I will not.

In the 80's I had Rix Rax switch machines.  I don't remember having any special capacitors and momentary push buttons.  I don't remember problems with the buttons or the 'old style Walthers Shinohara" turnouts.

 

Henry

COB Potomac & Northern

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Posted by rrinker on Thursday, February 6, 2020 9:37 AM

 I am using 30" as a minumum, I would never fit what I want in the space I have if I went 34" or 36", though it would look nice. And I'm already needing 2 decks.

2" spacing on tangent track is a good compromise between true prototype spacing and the fact that hands are 1:1 scale even if the trains are 1:87. Curves will need wider spacing depending on the equipment being used. 

TEST TEST TEST - there is no real 'rule of thumb' to determine that spacing. You need to try all possible combinations of various cars on the isndie and outside track. SOme cars that might not overhang ont he coupler ends might overhang more in the middle of the car. I found that out on a previous layout where I had a 30" inside track and 32" outside track. center spacing was increased beyond 2", but testing showed that certain cars needed even more. Luckily this was tested before any track was fastened down. 

I don't see any problems on my new layout with 30" - even the passenger cars I run will be the shorty type, as appropriate. No 80+ foot cars. 40' box cars and even shorter open hoppers look fine on 30" radius.

                                --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by riogrande5761 on Thursday, February 6, 2020 10:18 AM

Coastie71
Right now I'm planning on 30" radius outer and 27.25" inner track for the curves and probably 2 1/6" spacing for straight/tangent track.  I don't own any rolling stock or track yet so I can't test it out until right before I build, but currently trying to make sure that what I design will or should work.  I know the NMRA dose'nt recommend anything below 32" radius 2 1/2" spacing, I assume, inner track for longer cars, but I'm thinking if I increase the spacing an extra 1/4 inch I might be safe. 

I would think quite the opposite for longer cars ... you'd want to run them on an outer track so they would have a broader radius.

It's often a matter of compromise between givens and druthers, as John Armstong used to say.

My philosphy is to squeeze as much radius as possible for a given space.  Not all of us have the means/resources/space to have super broad curves, but with some careful planning and compromises, you may be able to squeeze a little broader curves into the design.  Every little bit helps.

In my case, my compromises ended with narrower benchwork and less generous walkways to get a long mainline run and 32 inch minimum radius curves - in two places and a 33-inch in another place.  The rest of the curves designed are in the 34 to 42 inch range.  It's looking like the helix will be 33 or maybe 34 inch radius.

So you may want to look at walkways, and any factors that may allow you to increase minimum curves, if at all possible.

Rio Grande.  The Action Road  - Focus 1977-1983

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Posted by BATMAN on Thursday, February 6, 2020 11:56 AM

riogrande5761
So you may want to look at walkways, and any factors that may allow you to increase minimum curves, if at all possible.

Yes, a little fine-tuning can make a big improvement to performance. Losing a couple of inches of standing around space is easily done by slapping a 1" x 4" along the edge of the layout.

This space between the benches is 17" wide and I can walk straight through with no issues, it opens up to a much larger area where I have my Captain's chair. Having this one narrow point passageway allowed me to have 34" radiuses. 

 

Skinny people have larger radiuses.Laugh

Brent

It's not the age honey, it's the mileage.

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Posted by rrinker on Thursday, February 6, 2020 2:33 PM

 I'd have to duck under that part, no way am I fitting through a 17" wide area, facing forwards or turned sideways. Bad enough I almost got stuck in that WWII sub I went through in Buffalo.

 You might think longer cars on the outer track is always best, but overhang varies a lot from car to car, and car type to car type. Long passenger cars often have a greater overhang from the bolster to car end, to the interference is fromt eh car end stickign out past the outer rail - they would go best on the other track. But a lot of those big 85' high cube cars have the trucks set farily out close to the ends  their overhang is the middle of the car hanging inside the inner rail. SO they would be best used on the inner track. Even this is a generalization. WHich is why I say test before making anything permanent. All possible combinations of different cars on the inside and outside tracks. Sometimes even what seems like a shorter car that shouldn;t possibly cause a problem is the troublemaker. The worst case would be the car witht he most end overhang on the inner track, trying to pass by the car with the most inside overhang running on the outer track.

 Don't forget locos - since model articulated locos rarely operate like the prototype, the front end can hang way out and if on the inner track, poke right into cars on the outer track.

                                                 --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by Coastie71 on Thursday, February 6, 2020 10:51 PM

Mel, thanks for the reply and information.  I'm not sure, but I think your talking track.  If not, I'm not going to have any track crossovers, just double wide bridges and tunnel portals and will take your and Sheldon's advice for 2" centers for straight track.

I've reworked my track plan based on Sheldon's advice and was able to get 32"R inner curve and 34.5"R outer curve with 2 1/2" spacing, which if I read the NMRA S-8 standard should handle the longest cars.

Thanks again, Gary (Coastie71)

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Posted by Coastie71 on Thursday, February 6, 2020 10:58 PM

Henry, thanks, I'll check those links out.  I don't remember what type of turnouts or switch buttons I used in the 80s, but the turnouts many times would never fully complete the motion.

Again thanks again for the help!

Gary

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Posted by Coastie71 on Thursday, February 6, 2020 11:07 PM

Randy, thanks for the input.  I did rework my track plan and was able to get the NMRA S-8 standard minimum 2 1/2" spacing with 32" inner/34.5" outer curve.  But I will take your advice about testing cars before I start laying down track.

I like your input about hands are 1:1 scale.

Thanks again, Gary

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Posted by Coastie71 on Thursday, February 6, 2020 11:27 PM

Rio Grande, thank you for your input.  I reworked my plan and was able to get 32" inner/34.5" outer curve (2 1/2" spacing), which I believe is what the NMRA S-8 standard is saying for maximum length cars.  I was also able to keep the 2 1/2' aisles throughout so I think I might be OK, but will test cars before laying track.  I was hoping to run the longer passenger cars in both directions on the double track, but if necessary will run only on outer curve.

I'm staying away from helix's and anything that will make this project too hard of an endeavor.  I'm more than a little intimidated by the amount of work it takes too build this size layout, but I put up a 30x40' steel building in the back yard just for this purpose and room for an 8' pool table, so I'm committed to getting it done.

Thanks again, Gary

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Posted by Coastie71 on Thursday, February 6, 2020 11:44 PM

Brent, thanks for your input.  I reworked my plan and was able to get 32"R inner curve/34.5" outer curve and actually able to keep my 2 1/2' aisles.

Appreciate the pictures and really liked your layout.  One question, did you use 1/2" or 3/4" plywood and what looks like up to 2" extruded foam and cork roadbed.  Not sure if your using Tortoise switch motors, but if so does the throw rod go through all that material?

Thanks again, and if I can get the Tortoise to work through all that material, that makes more sense for me to use the same concept.

Gary

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Posted by Coastie71 on Thursday, February 6, 2020 11:50 PM

Randy, thanks again for your great advice.  I will test everything before going to actual building and track laying.

Gary

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