By Thomas Dixon. This book is an overview history of the General Motors Electro-Motive Division GP7 and GP9 model diesel locomotives on the C&O.They were the backbone of C&O's first diesel fleet and were the main replacements for its freight service steam power. Many were later used by B&O after its affilliation, and some survived into late Chessie System and early CSX eras. All were gone by the mid-1980s. This C&O book covers their history and presents a color album showing these locomotives at work across the system. Softbound. 64 glossy pages.