Minimum radius for Williams 2 rail K-4

Well, I run my 3 rail Williams Crown K4 on 042, or 21" radius track.  If your 2 rail has the same wheelbase on the pilot truck, I would expect it will probably run on the same diameter track.  I am assuming of course that the only difference between the two rail and three rail engine's in that sense is smaller flanges.  That said, I will bow others who actually have both engine's and can say for sure.  You can pretty clearly see the elongated pilot on the Williams engine in the pic below compared to the Scalecraft and Lionel K4's behind.  I am hoping to find a 2 rail K4 as well sometime though.  I am sorry I can not directly answer your question,am somewhat interested to to see for sure how different the 2 & 3 rail K4's are.

Hi Denis,

Thanks for the reply,  I believe the 3 rail versions of the Williams also have the middle wheel set blinded where the 2 rail versions have flanges on all three sets of wheels.

I have an all nation/babbitt 4-6-0 an it requires a min 36 " radius (O-72) and was assuming the same for the Willams but as you point out the Williams is longer than the scale craft (Weaver) K-4.

John