Thank You both. It was the reversal of curves that grabbed my tiny mind. The 'path' mantra won't let go. Gerry, I'd bet money you have better. You've been at it longer & informed by this wonderful place longer. I'd love to be able to get an active train in the wider context or in motion - the way DWT has on his shots of mills & fab plants. Smoke/steam belching out of the mouth of a tunnel w/ the cow catcher & front of boiler bursting through the smoke. Yee Haw!