While both railroads were interested in what KM had to offer the builder had never before sold its locomotives in the United States. There were vast differences between American and European operations; the former's railroads utilized automatic knuckle couplers with locomotive cabs situated at one end while the latter's employed bumpers and either centered or double-ended cabs. After the final design characteristics were hashed out the locomotive's appearance was somewhat similar to the traditional covered wagon designs found all across the States, save for a longer carbody and turret-like cab that sat above the roofline and not flush as was the case with a typical Electro-Motive F3 or F7.
Dubbed the ML-4000, the locomotive employed a pair of Maybach MD870, 4-cyle, V-16 prime movers, rated at 2,000 horsepower each with a turbo-transmission manufactured by Voith. Krauss-Maffei rated the locomotive's continuous tractive effort at 78,000 pounds with a starting tractive effort up to 106,000 pounds. Testing of the new ML-4000 occurred between July 3-7, 1961 near the Austrian town of Semmering at a location known as the Semmering Incline. The stretch of track spanned 41.6 miles between Wiener Neustadt and Mürzzuschlag with grades reaching up to 2.52%. Following extensive trials railroad officials were pleased and believed the locomotives would perform well along the stiff main line grades found on the Rio Grande and Southern Pacific. For more information about the ML-4000's please click here.
Krauss-Maffei ML-4000 Cab Unit Roster
|Krauss-Maffei||Southern Pacific||ML-4000||1961||9000-9002 (In 1965, renumbered 9100-9102.)|
|Krauss-Maffei||Southern Pacific||ML-4000||1961||Ex-D&RGW 4001-4003, Numbered 9021-9023 (In 1965, renumbered 9103-9105.)|
|Krauss-Maffei||Denver & Rio Grande Western||ML-4000||1961||4001-4003|
Krauss-Maffei ML-4000 Hood Unit Roster
|Krauss-Maffei||Southern Pacific||ML-4000||1963||9003-9017 (In 1965, renumbered 9106-9120.)|
Mr. Morgan's article offered a glowing review of the ML-4000 and opinions from railroaders he interviewed generally gave the locomotive a favorable recommendation. The general sentiment noted it was reliable and much more powerful than the ubiquitous EMD covered wagon. One railroader proclaimed a singled ML-4000 was "equal to two F7's," a statement which largely held true, at least initially, once the KM's entered service on the Rio Grande. Upon delivery to the States on October 31, 1961, the original order of six was numbered 9000-9002 on Southern Pacific and 4001-4003 on the Rio Grande. Interestingly, while KM had the ML-4000 listed at 4,000 horsepower, their actual output in service, as per American designations, on the SP and D&RGW ranged from 3,000 to 3,450 horsepower.
In the February, 1962 issue of Trains Magazine, Mr. Morgan published another article highlighting the ML-4000's entitled, "A Week End In The Rockies With The KM's," where during November of 1961 he spent time observing the new locomotives in service on the Rio Grande. Once again they appeared to be performing admirably and meeting expectations. However, as time went on the D&RGW found the KM's unsatisfactory in rugged mountain service, eventually selling its trio to SP in 1964 which became #9021-9023. Southern Pacific came to a similar conclusion, relegating the original cab units to low-grade service in California's Central Valley. In 1963 SP returned to Krauss-Maffei for an additional 15 units (#9003-9017), which were virtually identical internally but featured a more road-switcher-like carbody, dubbed a "hood unit," with external walkways all around the locomotive.
In total, Southern Pacific's 21 units were originally numbered as follows; #9000-9017 and #9021-9023 (Ex-D&RGW). The units were later renumbered #9100-9120. Starting in 1966 with Electro-Motive's SD40, followed soon after by similar models from General Electric and the American Locomotive Company (Alco), American manufacturers could nearly match the ML-4000's horsepower with ratings of 3,000 and higher. This effectively ended the diesel hydraulic experiment (SP had also tested a similar design from Alco dubbed the C643DH) and most of the ML-4000's were parked and later scrapped. However, one was saved; hood unit #9113 (originally #9010) was converted into what it called a "Simulator Car" between 1968 and 1969 as a means of training engineers. It became SPMW #1 but later renumbered as 1166 and in 1969 was again renumbered as 8799. While extensively rebuilt, including the removal of its gearboxes and Cardan driveshafts, it did survive (including both of its prime movers) and following retirement in 1984 was later donated to the California State Railroad Museum. For further reading about SP's Krauss-Maffei's please click here.
It was later sold to the Pacific Locomotive Association (PLA), which has returned it to its #9010 number and worked extensively to completely restore the locomotive's carbody, including rebuilding its nose (mostly removed during its simulator years) and finding original gearboxes, trucks, and driveshaft replacements all of which came from Europe. This difficult task was a joint effort between the PLA and Southern Pacific Historical & Technical Society. The locomotive currently only carries a cosmetic restoration but long-term plans hope to see the unit run once again using one of its two on-board prime movers. Given the scope of the work involved once this occurs #9010 will truly be one of the greatest of success stories regarding a locomotive restoration.
(An additional thanks to Bob Zenk for help with the information in this article.)
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