The AAR wheel arrangement system is a method of classifying locomotive (or unit) wheel arrangements that was developed by the Association of American Railroads . Essentially a simplification of the European UIC classification , it is widely used in North America to describe diesel and electric locomotives (including third-rail electric locomotives ). It is not used for steam locomotives , which use the Whyte notation instead (except geared steam locomotives , which are instead classified by their model and their number of trucks).
65-529: The EMD SDP40F is a six-axle 3,000 hp (2.2 MW) 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
130-422: 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
195-412: 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. A series of derailments in the mid-1970s shattered Amtrak's confidence in the locomotive, and many railroads banned it from their tracks. Multiple investigations pointed to issues with
260-718: A hinge. Examples include the Milwaukee Road EF-1 "Boxcab" electrics. "B+B-B+B" means there are four trucks under the unit. Within each truck, there are two powered axles, and pairs of them are connected by span bolsters . One example would be the General Electric U50 , built from 1963 to 1965. The 4500 horsepower (3.4 MW) turbine locomotives built by GE for Union Pacific also used this arrangement. The EFVM railway of Brazil uses narrow gauge GE "BB" locomotives with this arrangement, both with "standard" and wide cabs. A GE Dash 9-40BBW , for instance,
325-521: 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
390-410: A pair of high-powered B-B locomotives on a common frame as far as traction and power was concerned). In fact, a usual consist of a D-D unit included a leading C-C unit and a trailing C-C unit, for a total of about 12,600 hp (9.4 MW) (with four total prime-movers). With today's higher horsepower C-C units (about 4,300 hp (3.2 MW) apiece), three such C-C units exceeds the total power of
455-566: 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
520-442: A row, "C" to three powered axles in a row, and "D" to four powered axles in a row. "1" refers to one idler axle, and "2" to two idler axles in a row. A dash ("–") separates trucks or wheel assemblies. A plus sign ("+") refers to articulation, either by connecting bogies with span bolsters or by connecting individual locomotives via solid drawbars instead of couplers . "1A-A1" means there are two trucks (or wheel assemblies) under
585-490: Is "Four axle". "B-2-B" means there are three trucks. The center truck has two unpowered axles and the truck at each end has two powered axles. The locomotive frame must either articulate or allow for significant side play to be provided to the center truck. Examples of this type were built as light rail vehicles. "B-B-B" means there are three trucks. Each truck has two powered axles. The locomotive frame must either articulate or allow for significant side play to be provided to
650-408: Is "Six axle". "1-C+C-1" means there are two sets of articulated axles under the unit. Within each of these sets, there is a truck with one idler axle, and inboard of it are three powered axles. Two of these articulated sets are placed back to back and connected by a hinge. The PRR FF1 and FF2 electric locomotives used this arrangement. "2-C+C-2" means there are two sets of articulated axles under
715-523: Is a guiding truck with two idler axles, and inboard of this, and hinged to it, is a truck with three powered axles. The GE steam turbine-electric locomotives of 1939 were notable examples of this arrangement. "2-C1+2-C1-B" means there are five trucks. Only the first three axles on the four-axle trucks were powered, as were both axles in the last truck; the first and middle trucks had two unpowered axles each. The only examples of this arrangement were three unique coal -fired steam-turbine locomotives built by
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#1732786909304780-584: Is a narrow-gauge adaptation of the SD45 , which required additional axles due to using smaller traction motors. "2-D+D-2" means there are two sets of articulated axles under the unit. Within each of these sets, there is a truck with two idler axles, and inboard of it are four powered axles. Two of these articulated sets are placed back to back and connected by a hinge. Examples include the Baldwin DR-12-8-1500/2 "Centipede" diesel locomotives and
845-751: Is a truck with two idler axles, and inboard of it are four powered axles. Two of these articulated sets are placed back to back and connected by a hinge. The Little Joes , Baldwin DR-12-8-1500/2 , and Baldwin 4-8+8-4-750/8-DE locomotives used this arrangement. "D-D" means there are two trucks each with four powered axles. Examples include the EMD DD units. D-D locomotives have fallen out of favor as nearly all of these were twin-engined locomotives, which placed too much horsepower in too few axles which made these consists rather inflexible (each locomotive featured two prime movers , making each unit essentially
910-399: Is a wide cab GE Dash 9-40CW series 4,000 hp (3,000 kW) locomotive with a B+B-B+B wheel arrangement. The EMD SD70ACe-BB produced from 2015 onward also has a B+B-B+B arrangement. "B-B+B-B" means that the locomotive has four trucks. Each truck contains two powered axles. The middle pair of trucks are connected by a span bolster . In most cases, the locomotive is articulated over
975-551: Is under the back of the unit, and has one idler axle. Examples include the three EMD LWT12 locomotives built by EMD in 1956. Twenty SD70ACe-P4 locomotives were built by EMD with a B1-1B arrangement that has two three axle trucks with each truck having two AC traction motors and one idler axle nearest the fuel tank. The locomotive was designed as an AC traction alternative to the SD70M-2 that uses three DC traction motors on each of two three axle trucks. Only BNSF ordered
1040-465: Is under the back of the unit, and has two idler axles in a row. Examples include the three lightweight RP-210 locomotives built by Baldwin in 1956 and 1957 for use with Pullman-Standard Train-X equipment. "B-A1A" means there are two trucks. The "B" truck is under the front of the unit, and has two powered axles. The "A1A" truck is under the back of the unit, and has one powered axle, one idler axle, and one more powered axle. Examples include some of
1105-546: Is under the front of the unit, and has one powered axle, one idler axle, and one more powered axle. The "3" truck is under the back of the unit, and has three idler axles in a row. An example is the Baldwin DR-6-2-10 1,000 hp (750 kW) cab unit, only one of which was built for the Chicago and North Western Railway in 1948. "A1A-A1A" means there are two trucks under the locomotive. Each truck has two powered axles, with an idler axle between them. This spreads
1170-539: Is under the front of the unit, and has three idler axles in a row. The "A1A" truck is under the rear of the unit, and has one powered axle, one idler axle, and one more powered axle. An example is the later built FM OP800 800 hp (600 kW) railcar, six of which were built by the St. Louis Car Company exclusively for the Southern Railway in 1939. "A1-1A" means there are two trucks or wheel assemblies under
1235-714: 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. 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
1300-902: The BNSF Railway , successor to the Santa Fe, until their retirement in 2002. One SDF40-2, ex-Amtrak No. 644 (later ATSF 6976), 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 . AAR wheel arrangement#C-C The AAR system (like UIC) counts axles, unlike Whyte, which counts wheels. Letters refer to powered axles, and numbers to unpowered (or idler) axles. "A" refers to one powered axle, "B" to two powered axles in
1365-758: The Baldwin Locomotive Works for the Chesapeake and Ohio Railway between 1947 and 1948. This locomotive is sometimes called the M-1. "C-C+C-C" means there are four trucks under the unit. Each truck has three powered axles. The only examples of this type were the 8500 horsepower (6.3 MW) turbine locomotives built by General Electric for Union Pacific . These locomotives consisted of two permanently coupled C-C units. "C+C-C+C" means there are four trucks. Each truck has three powered axles and pairs of them are connected by span bolsters . This arrangement
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#17327869093041430-834: The British Rail Class 28 are the only locomotives to use this wheel arrangement. "C-C" means there are two identical trucks. Each truck has three powered axles. Examples include the EMD SD (Special Duty), GMD GF6C , EMD GM6C , PRR E44 , GE E60 , Virginian EL-C and GE Evolution Series units, except the ES44C4 and ET44C4 which use the A1A-A1A wheel arrangement. This is a currently popular configuration used in low-speed, high-weight applications, such as unit coal trains. General ("manifest") freight trains also use C-C locomotives. See also Co-Co . An American colloquialism of "C-C"
1495-931: The FM C-liners (most passenger units) built from 1950 to 1955, and the EMD FL9 . "B-B" means there are two identical trucks. Each truck has two powered axles, a currently popular configuration used in high-speed, low-weight applications such as intermodal trains and high-speed rail , as well as switcher locomotives . Examples include the EMD GP (General Purpose), EMD F-units , EMD SW1500 , Acela Express Power Cars , Siemens Charger , Siemens ACS-64 and GE Genesis units. High speed ("time") freight trains, with guaranteed schedules often use B-B locomotives of 3,800 HP (950 HP per axle), but this application, too, has largely been replaced by higher-powered, 4,500 HP C-C locomotives (750 HP per axle). An American colloquialism of "B-B"
1560-488: 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
1625-621: The GE " Little Joe " electric locomotives . "B-D+D-B" means there are two sets of articulated axles under the unit. Within each of these sets, there is a truck with two powered axles, and inboard of it are four powered axles. Two of these articulated sets are placed back to back and connected by a hinge. The W-1 class of electric locomotives built by General Electric for the Great Northern Railway used this arrangement. "1B+D+D+B1" means there are four sets of articulated axles under
1690-535: The Great Northern Z-1 electric locomotives (for the Cascade Tunnel electrification) used this arrangement. "2-D-2" means there are three trucks. At either end are trucks with two idler axles; the center truck has four powered axles. The PRR R1 electric locomotive used this arrangement. "2-D+D-2" means there are two sets of articulated axles under the unit. Within each of these sets, theare
1755-492: The Southern Railway in 1939. "2-B" means there are two trucks or wheel assemblies. The "2" truck is under the front of the unit, and has two idler axles in a row. The "B" truck is under the rear of the unit, and has two powered axles. Examples include the three lightweight power cars built by ALCO / ACF in 1935 and 1937 for use with the Rebel streamliners. "3-A1A" means there are two trucks or wheel assemblies. The "3" truck
1820-546: The Texas Mexican Railway . "2-A1A" means there are two trucks or wheel assemblies. The "2" truck is under the front of the unit, and has two idler axles in a row. The "A1A" truck is under the rear of the unit, and has one powered axle, one idler axle, and one more powered axle. An example is the FM OP800 800 hp (600 kW) railcar, six of which were built by the St. Louis Car Company exclusively for
1885-578: The Virginian Railway 's EL-2B electric locomotives. EMD FP45 The EMD FP45 is a cowl unit type of C-C diesel locomotive produced in the United States by General Motors Electro-Motive Division (EMD). It was produced beginning in 1967 at the request of the Atchison, Topeka and Santa Fe Railway , which did not want its prestigious Super Chief / El Capitan and other passenger trains pulled by freight style hood unit locomotives, which have external walkways. The EMD SDP45
1950-459: The "1" truck is under the front of the unit, and has one idler axle. The remaining 4 axles are rigidly mounted to the frame behind this lead truck (or grouped in a second truck). This is roughly the equivalent of a 2-8-0 Consolidation in the Whyte notation, particularly when built as a 1-truck/4 rigid axle locomotive. The only known examples are a series of diesel boxcab locomotives built and owned by
2015-618: The 3,000 hp (2,240 kW) SD40-2 , the SDP40F . After the failure of the SDP40F, Amtrak traded 18 units to the Santa Fe, where they were converted for freight use. The converted locomotives were designated as SDF40-2. The last three F45s in service were on the Montana Rail Link and the New York, Susquehanna and Western Railway in the northern and northeastern United States. These units were taken out of service in 2006 for
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2080-707: The Amtrak roster in 1987. The remaining Amtrak SDP40Fs that weren't sold to the ATSF (seen below) are presumed to have been scrapped. 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
2145-806: The MRL and 2010 for the NYSW. Three are known to survive, with one located at the Izaak Walton Inn , now converted into a lodge. Between April 1980 and December 1982, Santa Fe 's San Bernardino shops rebuilt eight FP45s 5940–5943, 5945–5948. They emerged as 5990–5993, 5995–5998, and were redesignated SDFP45s. The 5944 was retired in September 1981 on account of a wreck at Toland, Texas. Electrically they were upgraded to SD45-2 standards. Mechanically, they were re-geared from 59:18 to 60:17, reducing their top speed from 89 to 83 mph (143 to 134 km/h). In
2210-505: The UK, the Class 31 uses this wheel arrangement. "A1A-B+B" means there are three trucks. The first truck has three axles, with the center one unpowered. A pair of two-axle trucks, each with both axles powered, are connected by a span bolster under the rear of the unit. The only example to date of this arrangement was a single experimental EMD SDP45 . "B" means there are two powered axles under
2275-437: 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
2340-505: The center truck. The Russian VL85 and US-American EMD GM10B was a notable example. See also Bo-Bo-Bo . "B+B+B" means there are three articulated sets of two powered axles each under the unit. The locomotive frame must allow for significant side play to be provided to the center axle set, as well as allowing for end play for the end sets. The ten Mexican Railway GE boxcab electrics of 1923 are examples of this wheel arrangement. "2-B+B-2" means there are two sets of articulated axles under
2405-438: The center trucks. "B-B+B-B+B-B" means that the locomotive has six trucks. Each truck contains two powered axles. The only known locomotives to have this configuration were the two EMD TR3 locomotives made of three permanently coupled B-B units, which had solid drawbars connecting the units instead of the typical couplers. "C" means there are three powered axles under the unit. They are not articulated relative to other parts of
2470-437: The generators was a 1,350-US-gallon (5,100 L; 1,120 imp gal) 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 2,150 US gallons (8,100 L; 1,790 imp gal) of water and 2,500 US gallons (9,500 L; 2,100 imp gal) of diesel. Provision
2535-463: 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
2600-503: The locomotive's trucks, the weight of the water and steam generators used for train heating, the rough and poorly maintained tracks, or the harmonic vibration of baggage cars behind the locomotive. In 1977, Amtrak decided to retire 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
2665-509: The locomotive. This arrangement is only used on very small locomotives (e.g. the PRR B1 ). This arrangement is sometimes referred to as 0-6-0 , the Whyte notation equivalent. "C-B" means there are two trucks. The "C" truck is under the front of the unit, and has three powered axles. The "B" truck is under the rear of the unit, and has two powered axles. The Japanese DE10 , DE11 , and DE15 and
EMD SDP40F - Misplaced Pages Continue
2730-523: The mid-1980s Santa Fe again re-geared them - this time to 62:15 for 71 mph (114 km/h). Milwaukee Road's FP45s were all sold for scrap in 1981 and 1984. Santa Fe SDFP45 No. 5944 was wrecked in 1981, Santa Fe SDFP45 No. 96 was wrecked in 1994 on Cajon Pass. While No. 91 was sold to the Wisconsin Central in January 1995, becoming their #6652 and the rest stayed in service right up until
2795-477: The model in 2014. The other locomotive with this wheel arrangement is the EMD SD70MACH , which is an SD70MAC rebuilt by Progress Rail for Metra and used for passenger service. In 2020, Metra approved of the purchase of 15 of these locomotives with options to purchase up to 27 more. "B-2" means there are two trucks. The "B" truck is under the front of the unit, and has two powered axles. The "2" truck
2860-629: 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
2925-500: 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 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
2990-560: 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
3055-509: The span bolster. The Union Pacific 's M-10002 diesel streamliner and New York Central 's T-Motor third-rail electric locomotives are examples of this type. This arrangement also includes locomotives made of two permanently coupled B-B units, such as some EMD FT units which had a solid drawbar connecting two units instead of the typical couplers. "B-B-B-B" means there are four trucks. Each truck has two powered axles. The locomotive frame must allow for significant side play to be provided to
3120-566: 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
3185-462: The unit. At each end, there is one unpowered axle and two powered axles, hinged to a set of four powered axles. Two of these articulated sets are placed back to back and connected by a hinge. The "Bi-Polar" electric locomotives used by the Milwaukee Road used this arrangement. "(B+B-B+B)+(B+B-B+B)" means there are 2 units, each with 4 trucks in a B+B-B+B wheel arrangement. An example was
3250-595: The unit. Each truck has one powered axle and one idler axle, with the idler axles to the outside. Examples include Budd RDC diesel multiple unit ( DMU ) cars. "1B-1B" means there are two trucks with a leading idler axle in front of two powered axles. This arrangement was used to upgrade the B-B arrangement of two EMC 1800 hp B-B locomotives owned by the Santa Fe Railroad in 1938, for greater stability at speed. "1-D" means there are two trucks or groups of axles;
3315-608: The unit. Each truck has one powered axle and one idler axle, with the powered axles to the outside. "A1A-2" means there are two trucks. The "A1A" truck is under the front of the unit, and has one powered axle, one idler axle, and one more powered axle. The "2" truck is under the back of the unit, and has two idler axles in a row. An example is the Silver Charger power car for the General Pershing Zephyr . "A1A-3" means there are two trucks. The "A1A" truck
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#17327869093043380-466: The unit. These axles are not articulated relative to other parts of the locomotive. This arrangement is only used on very small locomotives, such as the EMD Model 40 . It is also used on speeders . This arrangement is sometimes referred to as 0-4-0 , the Whyte notation equivalent. "B-1" means there are two trucks. The "B" truck is under the front of the unit, and has two powered axles. The "1" truck
3445-420: The unit. Within each of these sets, there is a truck with two idler axles, and inboard of it are three powered axles. Two of these articulated sets are placed back to back and connected by a hinge. The Pennsylvania Railroad 's GG1 and Companhia Paulista 's electric locomotives were notable examples of this arrangement. "2+C-C+2" means there are two sets of axles under the unit. Within each of these sets, there
3510-570: The unit. Within each of these sets, there is a truck with two idler axles, and inboard of it are two powered axles. Two of these articulated sets are placed back to back and connected by a hinge. The PRR DD1 and DD2 electric locomotives used this arrangement. "2-B+B+B+B-2" means there are two sets of articulated axles under the unit. Within each of these sets, there is a truck with two idler axles, and inboard of it are two powered axles, hinged to yet another set of two powered axles. Two of these articulated sets are placed back to back and connected by
3575-499: The usual D-D consist by 300 hp (220 kW) (with one fewer prime-mover than a usual D-D consist, thereby significantly improving reliability and dramatically reducing maintenance). Although the D-D arrangement is associated with twin-prime-mover locomotives of high power, this does not mean a D-D with a single high-power prime mover may be built in the future, nor does it exclude two-truck, eight-axle electric locomotive. The EMD DDM45
3640-462: 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 Amtrak's road diesel fleet were veteran E8s , E9s , F3Bs , F7s , and FP7s . These ranged from 7 to 24 years old and were due for replacement. The SDP40F
3705-540: The weight of the locomotive more evenly over the track and counteracts the tendency of trucks to oscillate at high speeds, which is a problem with two axle trucks. The idler wheels may be smaller than the powered wheels. Examples of locomotives with this wheel arrangement include the EMD E-units and ALCO PAs , which were high speed passenger locomotives, and the dual service FM Erie-built . BNSF took delivery of ES44C4 locomotives with this type of truck in 2009. In
3770-411: Was 57:20. Santa Fe purchased nine of the locomotives (road numbers 100 through 108), and the Milwaukee Road bought five for its passenger service (road numbers 1 through 5). The Milwaukee Road units were delivered without dynamic braking. Reportedly, Illinois Central Railroad was considering an order for five FP45s as well (EMD order #5742, serial #s 34952–34956), but canceled it. Such low production
3835-511: 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 645 E3 diesel prime mover , which developed 3,000 hp (2.2 MW). The locomotive had a gear ratio of 57:20. Maximum speed at full horsepower was 94 mph (151 km/h); the locomotive exceeded 100 miles per hour (160 km/h) in tests. The SDP40F
3900-544: Was a good passenger locomotive, but to the Santa Fe Railway it did not look the part. EMD therefore designed a lightweight "cowl" body to cover the locomotive, though it did not, as in earlier cab units , provide any structural strength, which remained in the frame. The cowl provided sleeker looks, better aerodynamics at speed, and allowed the crew to enter the engine compartment en route for diagnostics and maintenance. Final drive gear ratio for passenger service
3965-542: Was feasible and profitable for EMD since the locomotive was fundamentally just a re-clothed SDP45 . Power, as in the SDP45 , was from a V20 645E3 engine (or prime mover ) developing 3,600 hp (2,680 kW). A freight-only derivative, the EMD F45 , was sold in greater numbers (86) to Santa Fe, the Great Northern Railway , and the Burlington Northern Railroad . Amtrak bought a similar passenger locomotive based on
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#17327869093044030-416: Was fitted with a Leslie Controls SL4T (S4T) air horn . There were doubts at the time about Amtrak's long-term viability, so the locomotives were designed for easy conversion to freight locomotives should Amtrak cease operation. In the early 1970s Amtrak's passenger car fleet was steam-heated ; Amtrak's requirement called for two steam generators. These were located at the rear of the locomotive. Forward of
4095-494: 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
4160-473: Was the installation of lower-profile cooling fans and air horns to avoid clearance problems in the Eastern US. 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 Amtrak's first for new-build locomotives. Amtrak deployed
4225-679: Was used on the Jawn Henry coal -fired steam-turbine locomotive built by the Baldwin Locomotive Works for the Norfolk & Western Railway in May, 1954. "1-D-1" means there are three trucks under the unit. At either end are trucks with one idler axle; the center truck has four powered axles. The original 1904–1909 New York Central S-Motor third-rail electric locomotives (for the Grand Central Terminal electrification) and
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