SP 9010, Oakland California, April 1966. I had just over a year left in my USAF enlistment at Hamilton AFB. From time to time I'd drive over the beautiful San Rafael - Richmond Bridge
to visit my Uncle who lived in Oakland. Hang out, drink a cool one, watch some football. Once in a while, we'd go down to to the SP Oakland engine facility to see what was cooking.
Wow! A couple of Krauss-Maffei ML-4000's! My early indoctrination of never going anywhere without my camera paid off!
In 1961, the Denver & Rio Grande Western and Southern Pacific each ordered three ML-4000 diesel-hydraulics, from Krausse-Maffei AG of Munich. Southern Pacific re-ordered 15 units in 1963, represented by SP 9010. D&RGW, fed up with maintenance issues, threw in the towel and sold their initial order of three, 4001 - 4003, to the SP in 1964.
This so-called “Greenhouse Cab” configuration, often referred to as the “road switcher cab,” housed two Maybach MD-870 water-cooled, 4-cycle V-16’s. Each engine was connected to a hydraulic transmission, supplying mechanical shaft drive to the bogies, as seen in this diagram. Converting metrics to US, some insist horsepower was only 3,450, not 4,000.
It was rumored that engine crews were uncomfortable about sitting just above the spinning drive shaft between the motor and transmission!
Years later, we find the Europeans have embraced the diesel-hydraulic drive system big time. Take a look at this detailed explanation and animation, complete with smoking engine! I would consider the diesel-hydraulic drive system mechanical nightmare, as compared to the diesel-electric drive system - what do you think?
Krauss-Maffei dates back to 1838, when Joseph Anton von Maffei founded the first locomotive factory in Munich. The take-over of the J.A. Maffei Company by Krauss & Company in 1931 created Krauss-Maffei AG with company headquarters in Munich-Allach. The first military products were developed in the 1930s.
Amongst other equipment, the company delivered more than 6,000 half-track trucks. In 1963, the German Ministry of Defense selected Krauss-Maffei as prime contractor for series production of the LEOPARD 1 main battle tank, which was later, followed by the GEPARD self-propelled anti-aircraft gun and the LEOPARD 2 main battle tank.
Following the merger/acquisition model, Siemens AG owns the company now. The mechanical nightmare mercifully came to an end after six short years, with all units ending up on the scrap heap in 1967. Well, not all of them. SP 9113, nee SP 9010 shown above, was given an unusual reprieve! She was converted to "Camera Car" - a platform for shooting films to be used in locomotive training simulators.
See also "What the Heck was That?"