Details the development and operation of the RENFE 4000 class diesel-hydraulics. Ten were delivered by Krauss-Maffei in 1966-68, 22 by Babcock & Wilcox in 1967-69. They finished service in 1986-87. The book begins with a summary of the development of diesel-hydraulic traction in Germany, the V80 and V200 classes, and the worldwide use of Krauss-Maffei/Maybach locomotives. An account of the process leading up to the Spanish order follows, their operational history, technical construction and a discussion of their reliability. Spanish text. 160 pages 22x20 cm, many photos and drawings, sb.