I am running 042 and do fine most of the time, there are a few cars ( AF LIONEL BRAND) that don't quite like it.  Maybe its their trucks are more flexible than Lionel MTH.  

BTW. I only run modern version tinplate.

Last edited by Jushavnfun
Original Post

I run 20" radius which is quite close to your O42, of course though I am running S gauge and all on original Gilbert track.

For the most part I don't have trouble with anything I run.


Last edited by Rayin"S"

I have two layouts. The 12'-by-8' has an O-72 loop and siding on which I run the larger engines and passenger trains. My most recent purchase was an MTH Premier Boston & Albany Hudson that is so nice, I may never take it off the layout. The middle loop is O-54 with a passing siding and those tracks get the first-generation diesel engines, small steam and freight trains. The O-36 inside loop was added last and usually gets a diesel switcher and a short freight. The 10'-by-5' layout is just a loop of O-54 on which I run smaller engines, a few passenger cars and short freights. All track Atlas O. There's never enough room...


Last edited by MELGAR

9" radius..... on my N scale! 

11" is a little better though as a minimum for running scale length passenger cars.  I used to have decent 2x4 layout.  Need to build another one.

I'm running 3 inter-connected loops.  two outer loops of 072 and one inner loop of 031. 

Mainline 072 and bigger.  One yard lead 063.  I have two 041 switches ( no 3 axle power on these two switches) also  two 072 switches at two different spots between the two mainlines and all other switches are 0100.    99% (+) of track is GG and a little of Atlas.

One of the 072 switches in the upper right.


The 063 yard lead track in front of the freight cars and the cars are on 072 track.



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For tinplate, original O31 tubular. When I run modern on the f!oor, O72 Fasttrack.

Mikey,  what kind if engines do you run.  Wondering if you have any large engines 054 min in your yard?

In what way do your AF cars have a problem with 42" diameter?  Could it be a matter of putting a drop oil on the various pivot points on the trucks or loosening the attachment post to allow a little bit of play?  Or is it a matter of the body swinging too far out on curves (which can only be fixed by using a wider radius)?  Train too long so that it pulls the cars to the inside on curves?  

AFAIK, the reproductions are nearly identical to the originals - did AF use the same radius track as Lionel back in the day?

I have both 42" and 72" diameter.  Can't recall any problems, but don't remember if I've run my AF cars on the 42" or not.

STD 72 on the main level with five rail STD/O 42 on the upper level. My Standard Gauge AF cars run fine on it. I don't have the extra long AF cars though, but my Ives cars run fine on STD 42. I double head my 400e's and have them coupled. Double headed, they will only run on STD 72. They swing of the front end of the 400e will pull the tender of the other engine off the track on STD 42.

I run tubular rail now. I got rid of the standard gauge MTH plastic roadbed track.


I have two standard gauge loops - the inner loop has mostly STD 57 with a little STD 72.  The outer loop (closest to the wall) has mostly STD 42 with a few STD 57 curves.  I run the Ives Olympian train (with 4 cars) without problems on the loop with the sharp curves.  The same goes for my AF president's special pulled by a Lionel 392e.

72" on my outer 2 loops at home with 2 42" loops on the inside. At shows using the Standard Gauge squares I run 57" and 42".

Last edited by Captaincog

I have a modular standard gauge layout using O-84 and O-72.  Other than she is a little over weight, just like the owner, these radius’s work very well for everything that has been run so far. 

It all depends on what you want to run on the layout 

My early (1913 and before)  Lionel layout original split pin track 42" 

Ives layout 42" 56" & 72" 

The modern era layout will have 72, 84,& 96" ...big long trains need a big radius to play. 

Cheers Carey 

My temporary layout has an 084 outer loop, two 072 inner loops, with an 042 loop inside those loops. When I get to build my permanent layout, it will have two 084 loops surrounding the room with bridges connecting to the tables I am using now as theIMG_20200213_115247706 temporary layout. That inner island will have an 084 loop on the outside, an 072 loop inside that, and a 042 trolley line inside that loop.


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I use USA  O42 for my SDG floor layout with out any issues . Then again I don't own any large engines , one 384 and two 390s .  The largest of my cars are the Steven Girard set , all others are 500 series cars . IMG_0732


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Same for me as Bob Nelson - 87, 72, 42. I know that Kirk and Chris of USA track can make even wider curves, I'm tempted if I decide to build a fixed layout (mine is currently SGMA modules).  With all the BIG locos I make (Challenger, GG1, E1A diesels, Daylight and 30" passenger cars), 42 rarely used, but I still own a bunch of prewar, all of which can handle the tight curves. Seeing a 60 car freight train of 200 series cars on the SGMA layout is a sight to behold. Same goes for a super long string of early hoppers pulled by 3 42's.



At the club I have 5-Rail 72 (multi-gauge), 5 Rail 42 (Multi-gauge), 54 Gargraves, 72 Gargraves, 42 (figure 8 extended).

Current Tinplate layout

At home I have a Gargraves 68 and a loop of 72 multi-gauge.

Scott Smith


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The biggest advantage of larger diameter curves is that you can run longer trains.  The original 42" diameter curves were designed with trains limited to only a few cars in mind.  72" and 87" curves allow dozens of cars to be pulled without problems.

If you like MESG (Modern Era Standard Gauge) trains, 72" and larger curves may be required.  The wonderful Lionel Hiawatha and Vanderbilt sets require 72" curves as the minimum. To provide adequate clearance for these larger trains, 87" curves are required outside of the 72" curves on dual tracks.



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