SD45 6684 (Frisco 936) by Frisco.org Posted on May 31, 2016 SD45 6684 (Frisco 936) SD45 6684 (Frisco 936) at Memphis, Tennessee in July 1981 (D.M. Johnson). This entry was posted in BN Patched, RT Collection and tagged 6684, 936, Electro-Motive Division, SD45. Bookmark the permalink.