Clearance dimension for O36 Fastrak

I would buy your loco first and measure carefully.  Ask a few friends to bring their largest locos and do some firsthand research!  But I do think you would be safe at 6".  After all, that's the spacing Lionel used for its concentric curves: O48 - O36 = 12, divided by two (for either side of the oval) = 6" between mainlines.  This formula holds as you go from O48 to O60, O60 to O72, etc., although at larger radii you probably don't need 6" unless you're running articulateds and 21" passenger cars.

All that being said, I think you're wasting space and at 6" your parallel mainlines won't look very realistic.  I'll venture a guess that you could get away with 5.5," and probably much less on parallel straights.  The key is not to get the mainlines too close in curves, and especially when exiting out of a curve near an adjacent straight.  Sometimes you can reduce the overhang with an "easement"-  Use one piece of larger diameter curve to lead into the O36.  Of course you have to do the same thing when you come out of the curve, and this will take up more room.  But it'll pay dividends in terms of realism and reliable operation.

I like the transition era, and I'm not a fan of articulateds, so I can get my tracks closer than someone who wants to run Big Boys, 6-axle diesels, and long modern-era freight and passenger cars.  YMMV.

Thank you for that information. I like the idea of going with 5.5” on curves with the O48 leading in and out. Also keeping it more realistic would be good so going less in parallel straight sections would be good.   I probably should buy that engine first.

Just be careful with O48, you might have to use two sections of O60 instead.  Double-check how many curved sections it takes to make a circle, because this determines the angle the track is making at the end of the curve.  I remember that somehow the geometry of O48 is odd and it's not interchangeable with O36 in all cases.

I use SCARM for track planning.  It won't tell you the clearances.  But if you're comfortable with computers and software-based design, you might check it out!

I’ve used O36 on inside curve and 072-O36-O72 on the outside curve and it’s has worked well as the locos ease into the curve. I can run locos designed for O 54 and larger curves and haven’t had any issues. I can try and get a picture for you if that helps. I did read in the Lionel Fastrack book that if you go with the 6” spacing it’s designed that you shouldn’t have any issues at all. I hope that helps and good luck!

G

When planning track clearance, I generally refer to NMRA standards and practices.  I don't always stick to them, but it's a good place to start.

https://nmra.org/sites/default...enters_july_2017.pdf

Thanks TED S and GERHARDT for that info. Sounds like a great way to ease into the curve. I’ll play with those ideas but due to my limited space I don’t know if I’ll be able to use it.   I’ll check out that NMRA link LEHIGH74 provided and thanks for that too. 

Hey GERHARDT waaay up in Canada!  I tried using the 072-36-72 and it looks like it will work great. Thanks again.

Now I need to learn how to design my table layouts to be able to take apart easily.

Thanks.

BreakmanBill posted:

Hey GERHARDT waaay up in Canada!  I tried using the 072-36-72 and it looks like it will work great. Thanks again.

Now I need to learn how to design my table layouts to be able to take apart easily.

Thanks.

Great to hear BreakmanBill!  I wanted to get you some pictures over the weekend, but I'm actually building my second level so the curves/table were covered with plywood. You can check out the layout update I had done here:  https://youtu.be/779tc-jVX4A  and see how the O36 inner loop and O36/O72 combo looks. I have O60 switches to create a crossover between loops and that is working very well.  I've been really happy with it overall.  Let me know if you need anything else!

G