Originally Posted by MichaelE
A 22" radius will give a 44" half circle. On a 4x8 that leaves 2" on each side. Not much at all if the locomotive doesn't want to follow the curve.
Actually you wouldn't even have that much. The radius of track curves is measured from the center of the ties. Your 44" doesn't include the other half of the track on both sides. That adds up to the full width of an HO track section, which this old N-scaler is going to estimate as 1-1/4" (some HO modeler can provide a more accurate measurement) So, adding that to the 44" there would be a bit under 1-1/2" left on either side of the 4x8. Also there would be some overhang of cars and locomotives that would need to be allowed for.