Germany Built A 4,000 HP Monster — American Mountains Cooked It Alive

Germany Built A 4,000 HP Monster — American Mountains Cooked It Alive Subscribe: ‪@legendarylocomotives‬ The Krauss-Maffei ML-4000 was a German diesel-hydraulic locomotive that American railroads bought in 1961 hoping to solve their mountain hauling problems. Southern Pacific and Denver & Rio Grande Western were running eight to ten locomotives per train over the Sierra Nevada and Rockies, burning out traction motors constantly. The Germans offered 4,000 horsepower from a single unit using hydraulic transmission instead of electric motors. On flat ground in Texas and California's San Joaquin Valley, they worked perfectly. Three could replace eight American F7s. But in mountain tunnels, they failed catastrophically. The core problem: Krauss-Maffei designed the cooling system for German conditions where locomotives run at full throttle only 10% of the time. American mountain railroads ran at 45% full throttle. The hydraulic fluid overheated, turned to vapor, and the transmission stopped working mid-tunnel. D&RGW crews nicknamed them "Damned Krauts" and sold all three units to Southern Pacific by 1964. SP relegated them to flat territory where they actually worked fine, but that defeated the entire purpose of buying them. By 1968, the program ended and all units were scrapped except SP 9010, which became a camera car and was later restored by the Pacific Locomotive Association. The Maybach engine started again in 2017 after 48 years of silence. EMD responded with the SD40 and SD45 in 1966, and later the Tunnel Motors with air intakes at the bottom specifically designed for mountain tunnel operations.