It seems the subject of the jerky operation of 1711 somewhat = evaporated... But there is an interesting chart which I got from Russ Jackson. Boris -- Attached file removed by Ecartis and put at URL below -- -- Type: image/jpeg -- Size: 800k (819994 bytes) -- URL : http://lists.dementia.org/files/pittsburgh-railways/Pgh%20Grades.jpg