GP7s 533 and 573 by Frisco.org Posted on December 26, 2013 GP7s 533 and 573 GP7s 533 and 573 at Altamont, Kansas in December 1969. The third unit is unidentified. (Golden Spike Productions). This entry was posted in Slides and tagged 533, 573, Electro-Motive Division, GP7. Bookmark the permalink.