GP38AC 646 by Frisco.org Posted on January 29, 2015 GP38AC 646 GP38AC 646 at St. Louis, Missouri on June 26, 1975 on an inbound freight. Note the Gasometers in the background. This entry was posted in Slides and tagged 646, Electro-Motive Division, Gasometers, GP38AC. Bookmark the permalink.