Greetings All,
Locomotive Spotlight #2-2024
Electro Motive Division SDP40F
Welcome to another locomotive spotlight. Today the spotlight falls on the star crossed EMD SDP40F.
The Prototype
The EMD SDP40F was a six-axle 3,000 HP C-C diesel–electric locomotive built by General Motors Electro-Motive Division (EMD) from 1973 to 1974. Based on Santa Fe's EMD FP45, 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 company's long-distance fleet.
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. Amtrak deployed the original 40 locomotives on long-distance trains in the Western United States.
"10/18/76, AMT SDP40F 523" by OHFalcon72 is licensed under CC BY-NC-ND 2.0. To view a copy of this license, visit https://creativecommons.org/licenses/by-nc-nd/2.0/?ref=openverse.
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.
In late 1975 J. David Ingles called the SDP40Fs the "stars of Amtrak's 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 led to the end of its career as a passenger locomotive.
Between 1974 and 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.
"Old126629" by Bengt 1955 is licensed under CC BY-NC 2.0. To view a copy of this license, visit https://creativecommons.org/licenses/by-nc/2.0/?ref=openverse.
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 Amtrak's 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 F40PH's frame. Between 1977 and 1987 Amtrak traded 132 of the SDP40Fs back to EMD for F40PHRs. The SDP40Fs 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.
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 re-gearing 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.
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 returned to operation in November 2019, now running on the Nevada Southern Railroad.
The Culprit was Identified
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.
The Model
About twenty years ago I purchased an Athearn Blue Box FP45 / SDP40F for my youngest son, who is a B&O fan. The model ran reliably and saw use on his B&O passenger trains. He is now grown and on his own and has left me in charge of his fleet. As I experimented in adding the B&O to my model railroad operations as reported in my previous blog entry I sought to replace the B&O 9856 shell with an Amtrak shell.
Resources
Wikipedia: Source for prototype information.
Train Forum: Good discussion on the Amtrak SDP40s.
Final thoughts and comments
Three dollars!!! For three bucks I was able to get this locomotive onto the layout in a proper role that fits my modeling time line. Absolutely no buyers remorse with this purchase!!
It was interesting to research the prototype and learn about the harmonic rocking of the coupled up baggage cars that led its early retirement and the early corrective measures taken at other suspected causes.
Thanks for reading and watching!!!
See you soon.
