Amtrak
What was the operator of EMD SDP40F from 1973 to 1985?
EMD SDP40F The EMD SDP40F was a six-axle C-C diesel–electric locomotive built by General Motors Electro-Motive Division ( EMD ) from 1973–1974 . EMD built 150 for Amtrak , the operator of most intercity passenger trains in the United States . Amtrak , a private company but funded by the United States government , had begun operation in 1971 with a fleet of aging diesel locomotives inherited from various private railroads . The SDP40F was the first diesel locomotive built new for Amtrak and for a brief time they formed the backbone of the companys long-distance fleet . A series of derailments in the mid-1970s shattered Amtraks confidence in the locomotive , and many railroads banned it from their tracks . Multiple investigations pointed to issues with the locomotives trucks , the weight of the water and steam generators used for train heating , or the harmonic vibration of baggage cars behind the locomotive . In 1977 Amtrak decided to move on from the SDP40F in favor of the EMD F40PH , which was already in use on short-distance routes . Amtrak traded most of its fleet into EMD ; the components were incorporated into new F40PHs . The remainder were traded to the Atchison , Topeka and Santa Fe Railway ( ATSF ) for use in freight service . The Santa Fe rebuilt the locomotives and designated them SDF40-2 . The Burlington Northern Santa Fe Railway ( BNSF ) , successor to the Santa Fe , retired them in 2002 . One of them is preserved , that one being ex-Amtrak No . 644 . Background . Amtrak assumed operation of most intercity rail passenger service in the United States on May 1 , 1971 . Until then such services were operated by various private railroads . The private railroads chose to retain their second generation passenger locomotives for freight service , or to operate the various commuter services which , by law , did not pass to Amtrak . To operate these intercity services the Amtrak had to buy or lease from the private railroads whatever locomotives remained . This left Amtrak with an aging and mechanically-incompatible fleet of diesel locomotives . The mainstays of Amtraks road diesel fleet were veteran E units and F units , the newest of which were 10–20 years old and due for replacement . Design . The SDP40F was a full-width cowl unit . It was based on the EMD FP45 passenger locomotive and EMD SD40-2 freight locomotive . All three shared the EMD 645E3 diesel prime mover , which developed . The locomotive had a gear ratio of 57:20 . Maximum speed at full horsepower was ; the locomotive exceeded in tests . The SDP40F was fitted with a Leslie Controls SL4T ( S4T ) . There were doubts at the time about Amtraks long-term viability , so the locomotives were designed for easy conversion to freight locomotives should Amtrak cease operation . In the early 1970s Amtraks passenger car fleet was steam-heated ; Amtraks requirement called for two steam generators . These were located at the rear of the locomotive . Forward of the generators was a water tank . This tank rested above the floorline . The lateral motion of the water within was later implicated in several derailments . The primary underbody tank was split between water and diesel fuel , carrying of water and of diesel . Provision was made for eventual conversion to head-end power ( HEP ) , but it was never carried out . EMD based the SDP40F name on the existing SDP40 . Several years earlier , EMD had made similar versions of the SDP45 and SD45 in a full-width cowl unit , which it named FP45 and F45 . Although the SDP40F was externally nearly identical to the FP45 , EMD chose not to give the new locomotive a similar name such as FP40 . EMD wanted to avoid adding a new locomotive type to their catalog due to price controls in effect in the early 1970s . The following year , the F40C name was used for a similar locomotive ordered by the Chicago , Milwaukee , St . Paul and Pacific Railroad ( the Milwaukee Road ) , equipped with HEP instead of steam generators . There were several minor differences between the first 40 locomotives built and later examples . The most important was the installation of lower-profile cooling fans and air horns to avoid clearance problems in the Eastern US . History . Amtrak ordered 150 SDP40Fs , in two batches . The first order , placed on November 2 , 1972 , was for 40 locomotives , at a cost of $18 million . A second order , for 110 locomotives at $50 million , followed on October 12 , 1973 . These orders were Amtraks first for new-build locomotives . Amtrak deployed the original 40 locomotives on long-distance trains in the Western United States . The locomotives entered revenue service on June 22 , 1973 , hauling the Super Chief from Chicago to Los Angeles over the Atchison , Topeka and Santa Fe Railway . SDP40Fs were also used on the Burlington Northern Railroad . The arrival of the second order enabled Amtrak to deploy the SDP40Fs throughout the country , displacing the inherited E-units . Derailments . In late 1975 J . David Ingles called the SDP40Fs the stars of Amtraks long-distance trains , but engine crews reported that the locomotives rode poorly compared to the E-units they had replaced . Even as Amtrak and EMD investigated the ride quality , the SDP40F was involved in a series of derailments that would lead to an end to its career as a passenger locomotive . Between 1974–1976 the Federal Railroad Administration ( FRA ) identified thirteen incidents for which the locomotive was responsible . None of the incidents were serious , but their frequency was a concern . Most of the derailments occurred on trains with two SDP40Fs on the front and at least one trailing baggage car . While the rear truck of the second locomotive and the front truck of the baggage car were pinpointed as the source of the derailment , the actual cause of the derailments was unclear . EMD , Amtrak , the Association of American Railroads ( AAR ) , and the FRA tested the locomotive thoroughly , with suspicion falling on the hollow bolster truck design . In the end , the investigators theorized that the steam generators and water tank may have made the rear of the engine too heavy and created too much lateral motion . Later FRA investigations concluded that the actual culprit was the light weight of the baggage cars , which caused harmonic vibrations when placed directly behind the much heavier SDP40F . A contributing factor was the sometimes poor quality of track the locomotive operated over . Amtrak took several corrective measures , including operating with a reduced speed on curves , emptying the smaller of the two water tanks to reduce lateral motion , and making various alterations to the trucks . The measures helped , but the trouble continued . Several railroads , including the Burlington and the Chesapeake and Ohio Railway ( C&O ) , banned the rail breakers from their tracks ; they were suspected to be causing the spreading of rails because of their lateral swaying , which may have contributed to the derailments . For the Chicago–Seattle Empire Builder , the speed restrictions added 6 hours to what had been a 46-hour schedule . Another important development was the unusually harsh winter of 1976–1977 , which sidelined many of Amtraks aging steam-heated coaches . Amtrak suspended numerous routes and pressed the new HEP-equipped Amfleet I coaches , designed for short runs , into service . The new EMD F40PH , intended for short-distance service and equipped with HEP , handled these trains . In the spring of 1977 Amtrak faced a power crisis . In addition to the SDP40Fs derailing , Amtrak was having trouble with two other six-axle designs . The GE E60CP and E60CH electric locomotives were having derailment problems . The GE P30CH had the same truck design as E60s and rode poorly , although it did not exhibit the same tendency to derail . Amtrak decided to abandon the SDP40F in favor of the F40PH , a four-axle design with none of the riding problems of the six-axle locomotives . Amtrak traded 40 SDP40Fs back to EMD . Components including the prime mover were installed into an F40PHs frame . Between 1977–1987 Amtrak traded 132 of the SDP40Fs back to EMD for F40PHRs . The SDP40F remained in service on the Santa Fe longer than elsewhere , although the arrival of HEP-equipped Superliner cars on the Western routes displaced them from there as well . The last SDP40Fs left the Amtrak roster in 1987 . The remaining Amtrak SDP40Fs that werent sold to the ATSF ( seen below ) are presumed to have been scrapped . Freight use . In 1984 Amtrak , low on light-duty power , traded 18 SDP40Fs to the Santa Fe for 43 switchers : 25 CF7s and 18 SSB1200s . Santa Fe rebuilt the traded locomotives for freight use . Modifications included removing the steam generators and regearing for lower speed . The locomotives were also given front steps and platforms , and notched noses in order to improve boarding access . The rebuilt locomotives were designated SDF40-2 . The SDF40-2s continued in service with the BNSF Railway , successor to the Santa Fe , until their retirement in 2002 . Preservation . One SDF40-2 , ex-Amtrak No . 644 , was acquired by Dynamic Rail Preservation Inc . and is in Boulder City , Nevada having been previously displayed in Ogden , Utah . It has been renumbered to its Santa Fe-era 6976 number and returned to operation in November 2019 . External links . - Santa Fe SDF40-2s on Santa Fe Subjects