Another ATSF Admirer

NMRA gauge sitting on Helix Support

Using the NMRA gauge to show the problem with a 1" wide spiral helix. In particular note how the left side of the gauge sits atop the line between '51' and '100' Also note how close the '100' step is to the diagonal corner

NMRA gauge sitting on Helix Support
Another ATSF Admirer, May 4, 2008