This volume provides a detailed examination of the motive power utilized by the Southern Pacific Railroad during the 1966-67 period. It aims to document the specific locomotives, their specifications, and their operational context within the railroad's network during this transitional era. The content is derived from official railroad records and photographic archives.

This publication is recognized as a specialized reference for railroad enthusiasts and historians focusing on the Southern Pacific. Its value lies in its detailed technical information and photographic record of a specific period in the railroad's operational history. The content is likely to appeal to those with a deep interest in locomotive technology and the evolution of rail transport.