I.m stuck in a wheelchair healing a back injury ..... can't get downstairs to my layout .... only have access a little test track section. Someone is bringing me some track so I can put together a little loop
Fastrack circles are measured from outer edge of the plastic ballast to outer edge of the plastic ballast, right?
While Lionel tubular track ...... an 031 circle is 31 inches from center rail to center rail.
Do I have that right?
Thanks
Jim
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I've heard conflicting reports regarding how Lionel tubular track is measured -- one says outside rail to outside rail; the other says outside of the ties. There's enough "give" in the curves to squeeze or stretch about an inch out of a half-circle without affecting operation.
I just ran into this question spacing concentric curves for a layout. My measurements indicated that the circle diameter of Lionel tubular track was approximately aligned to the outer rail, not the center. Two caveats: The numbers weren't all that precise, and I didn't measure any 031 because my minimum curve is 042.
And I hope your back heals quickly.
I think Fastrack is measured from the center track, not the edge.
I think Fastrack is measured from the center track, not the edge.
Yes, I think that is correct. And tubular track numbers (except O72) indicate the overall diameter of the track footprint across the outside of the ties, if you assemble a complete circle. And yes, tubular track is somewhat springy so it can be fudged - for example, I have a reverse loop with O27 curves that I tightened to 26" overall diameter, without kinking it.
This is a loaded question.
Lionel O-72 is 35.88" center rail radius(pretty darn close to O-72)
Lionel O is 14.14" center rail radius(O-28.28)
Lionel O-27 is 12.37" center rail radius(O-24.74)
Lionel O-36 Fastrack, & Super-O, are 18" center rail radius(O-36)
GarGraves sectional track is different even between plastic tie & wood tie track within their product line.
In 1986 Lionel published "The Lionel Train Book". Page 37 deals with the different type of track. According to their diagrams, the track diameter is measured from the ties and not the outer rail. I am not sure about Fastrack or other manufacturers.
Lionel Fastrack is measured center rail to center rail, as is, I think, Atlas (Atlas 72" curves fit exactly atop Fastrack 72") but I think a few other companies mean outer rail to outside rail instead, when they say O-31 - so their would be tighter than Lionels.
Here is a replay from Lionel in response to someone's question about Fastrack.
The FasTrack in the Polar Express set is O-36. A quick way to confirm this is to assemble a circle of track and lay a yardstick across it. An O-36 curve will be wider than the yardstick (on account of the 36″ being the diameter at the centerline of the track.) Even though the Polar Express train will negotiate a tighter curve, we include O-36 with all our FasTrack sets. Modelers with older O-27 curves can still use this train too however.
Just got back from local toy train shop. I measured the loop of O36 in window display at just under 35 3/4-inch center rail to center rail.
So guess Lionel uses rough framing carpenter tolerances.
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