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My question is what spacing is being used for two track mains? I'm trying to come up with a number for HO, but to many numbers come in my head. I know the statement "it's my layout I can do what I want", but I still need some help.

Thanks,
~Eric~
 

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It depends on your 'needs'.

Do you need to pick up items to re-rail them? If so, wide enough to get your fingers in there without doubling your work because you knocked off the car on the other side of your fingers.

If you need it to look prototypical, about 2", as stated by wvga.

If you need longer cars and parts of locomotives to pass safely on curves, you'd need about 3.5" for curves in the 24-28" radius range, a bit more for curves under 24", and a bit less for radii greater than about 30".
 

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Three and a half inches for that much radius?

303mm cars pass safely on my layout at 2-1/4" spacing on 24" and 22" curves.
 

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mainline spacing ~2.3/8" on center

on my layout 2 3/8" center on approximately
It's a double mainline figure eight on a 5'x9' train board.
Plans were taken from Atlas model railroad plans
most of my cars are 40 footers
Regards, tr1
 

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2" minimum (mine are 20 and 22.5).
Still no room for a tall signal between tracks without 50' freight cars colliding with the signal.
 

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Three and a half inches for that much radius?

303mm cars pass safely on my layout at 2-1/4" spacing on 24" and 22" curves.
I use large articulated steamers and the Pennsy T1 Duplex. My worst offender for sideswiping is the Rivarossi HO Chesapeake & Ohio H-8 2-6-6-6 "Allegheny". If I have it on a curve of 33", my minimum, and run past it with Walthers Heavyweights, they'll make contact with anything less than 3" separation. For prototypical separation, you'd want about 3.5", and that gets a fingertip in there as well.
 

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the figure i stated was the 'recommended practice' by the NMRA site .. you easily can add more for hand clearance, etc ... and the curves have more between the tracks to allow for overhang ..

this 'overhang' can vary depending on the tightness of the curve, and length of th rolling stock, plus clearance for stuff like signals, fingers, etc ..
 

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My question is what spacing is being used for two track mains? I'm trying to come up with a number for HO, but to many numbers come in my head. I know the statement "it's my layout I can do what I want", but I still need some help.

Thanks,
~Eric~
Eric,

On page 81 in "Track Planning for Realistic Operation" John Armstrong recommends the following for HO:

Radius Track Center Spacing

18 2-3/8"

24 2-1/4"

30 2-1/8"

tangent 2"

It's a book well worth having for all those pesky, technical matters in track and layout planning.
 

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Eric,

On page 81 in "Track Planning for Realistic Operation" John Armstrong recommends the following for HO:

Radius Track Center Spacing

18 2-3/8"

24 2-1/4"

30 2-1/8"

tangent 2"

It's a book well worth having for all those pesky, technical matters in track and layout planning.
I had the exact same question myself two weeks ago and got the same answer from the same book. I have an old version, but I end up referring to it often. Additionally, I asked some fellows whose opinion I respect and they referenced their answers from the same book!

I have a 26" outer flextrack radius and will be going with 22" sectional track for the inner, possibly with an inch or two added to the center. If I'd thought ahead, I could have gone with a 27" outer and then I could have used 24" radius Atlas sectional.

Oh well, no biggie. Would have been nice, but I'm sure it's not the last time on this layout that hindsight will have better clarity than foresight.
 

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You won't be sorry. It's by no means the most current or most visually exciting railroad book I own, but it's one of my most frequently referred to.
It's an excellent book - I have a very early version I inherited from my grandfather - it explains railroad concepts and the *reason* for laying out tracks in certain ways quite well and doesn't really go out of style. There's a reason Kalmback keeps re-publishing new editions.

His suggestions of establishing clear standards for your layout are also well worth heeding.
 
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