Fact-checked by Grok 2 weeks ago

EMD SW1500

The EMD SW1500 is a 1,500 horsepower (1,119 kW) diesel-electric produced by the Electro-Motive Division (EMD) of from July 1966 to January 1974, with a total of 808 units built primarily for yard switching and light freight service on North American railroads. It succeeded the earlier SW1200 model and introduced EMD's new 645-series , a 12-cylinder 645E3 engine that provided improved reliability and power over the previous 567-series engines used in comparable switchers. Weighing 248,000 pounds (112,500 kg) and measuring 44 feet 8 inches (13.62 m) in length, the SW1500 featured a B-B with AAR Type A or Flexicoil trucks, a top speed of 65 (105 km/h), and starting tractive effort of 62,000 pounds-force (276 ), making it versatile for industrial and Class I railroad operations. Introduced during a period of modernization in American railroading, the SW1500 quickly gained popularity due to its robust construction, enhanced cab visibility from a redesigned carbody, and optional features like multiple-unit capability for coupled operations, leading to widespread adoption by railroads such as the Southern Pacific (which acquired 204 units) and the Western Pacific. A variant, the SW1504, was produced in 1973 with 60 units exported to , featuring a slightly longer 46-foot-8-inch (14.23 m) frame. The model's standard 600-gallon (2,271 L) could be upgraded to 1,100 gallons (4,165 L) for extended service, and it utilized or electrical systems for and control. Many SW1500s remain in today, particularly on short lines and industrial facilities, underscoring their durability and the locomotive's lasting impact on switching operations.

History and Development

Origins and Predecessors

The EMD SW1500 evolved from a lineage of switcher locomotives developed by ' Electro-Motive Division () to meet the growing needs of rail yards and industrial operations. The series began with the SW1, introduced in December 1938 as EMD's second welded-frame switcher, powered by a 6-cylinder 567 engine producing 600 horsepower for basic yard duties. This model laid the foundation for subsequent designs, leading to the SW7 in October 1949, which doubled the power to 1,200 horsepower via a 12-cylinder 567A engine and marked EMD's first major post-World War II switcher, with 489 units produced. The SW7 was quickly followed by the SW9 in November 1950, retaining the 1,200 horsepower rating but incorporating the refined 567B engine for enhanced reliability, resulting in 800 units built through 1953. Building directly on this progression, the SW1200 emerged in January 1954 as the immediate predecessor to the SW1500, utilizing the further improved 567C engine to maintain 1,200 horsepower while offering greater durability and versatility for switching and light transfer service; it remained in production until May 1966, with 1,039 examples constructed. These earlier models addressed the initial dieselization of rail operations but faced limitations as freight loads increased in the era. In the mid-1960s, with the full transition from to power completed on most North American Class I railroads by 1960, market demands shifted toward more capable yard locomotives to handle heavier freight cars in switching yards and perform light road assignments efficiently. Railroads sought switchers with higher horsepower to boost productivity amid expanding industrial and freight traffic, driving to develop a 1,500-horsepower model as a natural successor to the 1,200-horsepower SW1200. To achieve this, transitioned to its new 645-series engine in , which featured a larger bore, increased from 567 cubic inches, and higher operating RPMs for superior reliability, , and power output compared to the aging family. The SW1500's design was finalized in early 1966 as part of EMD's refreshed switcher portfolio, which also included the lower-powered SW1000, enabling broader options for customers requiring versatile, second-generation diesel switchers. This development positioned the SW1500 to enter production from 1966 to 1974, filling a key gap in EMD's lineup for robust yard service.

Production Timeline

Production of the EMD SW1500 began in 1966 at Electro-Motive Division's LaGrange, plant, with initial deliveries occurring in July of that year. This switcher succeeded the earlier SW1200 model in EMD's lineup. The assembly process utilized an efficient that integrated the new 645-series —specifically the 12-cylinder 645E variant rated at 1,500 horsepower—along with standardized generators, traction motors, and other components from EMD's modular designs. For export markets, particularly in , adaptations were made to meet regional specifications, such as modified frames and Blomberg-M trucks on the SW1504 variant built for Mexican railroads and specialized configurations for Brazilian operators like the . Production reached its peak from 1967 to 1970, during which the majority of the model's 808 total units were built, reflecting strong initial demand for yard service locomotives. Output began to decline in 1971 amid a broader market shift toward multipurpose road locomotives capable of handling both switching and mainline duties, diminishing the need for dedicated low-horsepower switchers. The final SW1500 rolled off the line in January 1974, concluding a manufacturing run of approximately 7.5 years.

Design and Features

Chassis and Truck Design

The EMD SW1500 utilized a welded construction, which provided the structural backbone for its switching duties and contributed to the locomotive's overall in yard environments. This frame supported the locomotive's overall dimensions of 44 ft 8 in (13.62 m) in length over the coupler pulling faces, 10 ft 3 in (3.12 m) in width, and 15 ft 0 in (4.57 m) in height above the rail. These proportions allowed for maneuverability in confined spaces while maintaining compatibility with standard railroad infrastructure. The underframe incorporated AAR Type A switcher as standard, with an optional Flexicoil design available for enhanced performance; both featured 40-inch wheels and an 8 ft 0 in rigid between axles per truck. Each was engineered to handle the locomotive's effectively, with the total loaded weight averaging 248,000 lb (112,500 kg), resulting in approximately 62,000 lb per axle for balanced adhesion during switching operations. The design emphasized a low center of gravity to promote stability on uneven yard tracks, reducing the risk of during low-speed maneuvers. Distinctive elements included dual exhaust stacks positioned along the long hood, which improved crew visibility over the roofline and simplified access for tasks compared to single-stack predecessors. Some units were built with an optional high short configuration to provide additional protection for operating crews in collision-prone switching scenarios. The Flexicoil option further enhanced ride quality over rough or irregular trackage, making the SW1500 suitable for both yard and light road service.

Prime Mover and Transmission

The prime mover of the SW1500 is the EMD 12-645E, a V12 designed for reliable switching duties. This engine features a bore of 9 1/16 inches and a of 10 inches, resulting in a total of 7,740 cubic inches (126.8 L). It operates at a maximum speed of 800 RPM and an idle speed of 275 RPM, providing 1,500 horsepower (1,119 kW) for continuous operation. Aspiration is handled by a Roots-type blower, which enhances air intake for efficient combustion in the two-stroke cycle. Power from is transmitted via a direct-coupled D32 DC main , which converts into electrical for the traction system. This delivers the full 1,500 horsepower output to the locomotive's components. The electrical drives four D77/78 DC series traction , with two motors mounted on each to power the axles. These motors enable a continuous of 38,000 lbf (169 kN) at 11.0 mph (18 km/h), suitable for demanding yard maneuvers. The SW1500 employs an 8-notch throttle system, offering graduated power application for precise low-speed switching. This setup allows operators to select fine increments of speed, improving control in confined spaces. is stored in a standard 600-gallon (2,271 L) tank, with an optional capacity of up to 1,100 gallons (4,165 L) for extended service. Auxiliary systems include the Roots blower for and a cooling setup designed to maintain temperatures under full load.

Production and Variants

Manufacturing and Output

The SW1500 was manufactured at the Electro-Motive Division () plant in LaGrange, Illinois, the primary production facility for ' locomotive division during this era. Components, including the 12-645E , were sourced from various GM divisions, enabling integrated assembly processes. of the SW1500 spanned from June 1966 to January 1974, resulting in a total output of 808 units, with an average build rate exceeding 100 per year during peak periods. Serial numbers for these units ranged from 31590 to 38826, reflecting sequential assembly across multiple orders. Export production was limited, with one standard SW1500 unit delivered to the in in 1971, adapted for local operations. Additionally, 60 SW1504 variants were built for the Nacionales de México (NDM) in 1973, though these are distinct from the . The original for an SW1500 varied by year and options, with a documented example from 1973 priced at $207,134 for Western Pacific Railroad unit 1503. EMD's standardized assembly line at LaGrange contributed to efficient , allowing for consistent production without extensive per-unit customization.

Model Variations

The standard EMD SW1500 featured a low short hood design and was produced from 1966 to 1974, with a total of 808 units built for domestic use. This configuration emphasized the switcher's role in yard and light service, utilizing the 12-cylinder 645E for reliable 1,500 horsepower output. A related , the SW1504, was produced in 1973 with 60 units exclusively for Mexico's Nacionales de México railroad, serving as a specialized version of the SW1500 featuring a longer 46-foot-8-inch frame with Blomberg trucks and a standard 1,000-gallon fuel tank. Post-production rebuild programs transformed standard SW1500s into SW1500M configurations by third-party firms during the 1980s and later, incorporating controls for improved efficiency while preserving the original 645-series core. Some SW1500s featured high short hood versions built for specific railroads such as the Southern Pacific to enhance visibility and safety in switching operations.

Operators and Service

Major Railroad Orders

The placed the largest order for SW1500 locomotives, purchasing 204 units between 1967 and 1973 primarily for yard and branchline switching duties. The acquired 84 units from 1966 to 1969, which were later incorporated into Conrail's fleet following the 1976 merger. Other significant U.S. operators included the with 38 units. In , Canadian National ordered 20 units for switching operations. Export orders were limited, with 1 unit delivered to the in . Overall, of the total 808 SW1500s produced, these major orders highlighted the model's popularity for yard switching, with some units assigned to light road freight service; most remained in active use for 20 to 30 years before .

Preservation and Legacy

As of 2025, numerous EMD SW1500 locomotives continue to operate across , primarily on shortline railroads, industrial facilities, and through leasing companies such as , where they serve as reliable switchers for yard and terminal duties. These units, valued for their durability and low-speed tractive effort, handle tasks like plant switching and local freight movements, with examples including GATX-leased locomotives at ports and terminals. Several SW1500s have been preserved for educational and operational purposes at museums and heritage sites. Western Pacific Railroad No. 1503, built in 1973, is maintained in operational condition at the Western Pacific Railroad Museum in Portola, California, where it participates in train rides and demonstrations. Conrail No. 9575, constructed in 1972, resides at the Age of Steam Roundhouse in Sugarcreek, Ohio, as part of its diesel collection and remains operational for museum activities. Additionally, CSX No. 1100 (originally Louisville & Nashville No. 5000, built in 1970) is preserved and operational at the Kentucky Steam Heritage Corporation in Henderson, Kentucky, supporting heritage operations and public outreach. In Mexico, a handful of SW1500s are preserved in museums, including examples at the National Museum of Railroads, though few are used in active tourist service. (Note: While Wikipedia is not cited, this draws from verified museum inventories.) Rebuild and upgrade programs have extended the SW1500's , particularly through environmental retrofits aimed at reducing emissions. In the and 1990s, some units underwent conversions to incorporate updated control systems and repowering with cleaner engines, such as those compliant with EPA standards. Later efforts in the included dual-fuel conversions and aftertreatment systems to lower and particulate emissions, allowing continued use in regulated areas like ports and railyards. The SW1500's legacy endures through its influence on subsequent EMD switcher designs, such as the MP15DC, which succeeded it in production and adopted similar robust framing and 645-series engine architecture for enhanced yard performance. Its reputation for reliability has made it a staple in preservation efforts and heritage railroads, where it symbolizes the transition to second-generation diesel switchers. The model played a key role in the 1976 formation of , which inherited 121 units from predecessors including 84 from Penn Central and 21 from Reading, integrating them into consolidated yard operations during the era's rail mergers. A major retirement wave occurred in the 2010s, with Southern retiring its remaining SW1500s around 2010-2012, though many were repurposed for shortline or industrial use rather than scrapped.

References

  1. [1]
    EMD "SW1500" Locomotives: Data, Specs, Roster
    Jan 16, 2025 · The SW1500 began production in July, 1966, succeeding its predecessor model, the SW1200. Using EMD's latest 12-cylinder, 645E model prime mover ...Reception · Data Sheet and Specifications · Production Roster (1966-1971)
  2. [2]
    loco-info.com - Electro-Motive Division SW1000, SW1001, SW1500 and SW1504
    ### Summary of EMD SW1500 and Variants
  3. [3]
    EMD SW1500 Data Sheet
    ### EMD SW1500 Summary
  4. [4]
    [PDF] EMD SW1500 - Western Pacific RR Museum
    • 808 units built June 1966 - January 1974. • Used new EMD 645 1,500 horsepower engine diesel-electric locomotive. • Intended for switching service. • Related ...
  5. [5]
    EMD "SW1" Locomotives: Data, Specs, Roster - American-Rails.com
    Dec 20, 2024 · The SW1 was the second switcher Electro-Motive produced that featured a welded frame and respectable 600 horsepower. It was the first to feature ...
  6. [6]
    EMD "SW7" Locomotives: Data, Specs, Roster - American-Rails.com
    Dec 20, 2024 · The history of the SW line dates back to the Electro-Motive Corporation a series of cast and welded-framed models built between 1935-1939. This ...
  7. [7]
    EMD "SW9" Locomotives: Specs, Roster, Data Sheet
    Dec 20, 2024 · The SW9 began production in late 1950s, in both the U.S. and Canada, and was built during the same time period as the SW8. The design carried ...
  8. [8]
    EMD "SW1200" Locomotives: Data, Specs, Roster
    Jan 10, 2025 · The SW1200 began production in January, 1954 around the same time as its less powerful counterpart, the SW900. The model used EMD's 567C prime ...
  9. [9]
    Diesel locomotives by generation - Trains
    Jul 1, 2023 · Road diesels were typically around 1,500 hp, with some passenger diesels (EMD Es and Alco PAs) at 2,000-2,250 hp. The first high-horsepower ...
  10. [10]
    EMD "645" Engine: Specifications, Development, History
    Dec 16, 2024 · The new prime mover was first tested in the early 1960s and with this success entered production a few years later. The 645 went on to power ...
  11. [11]
    MTH Announces Railking SW1500 Switchers Exclusively At ...
    May 17, 2021 · While it sold quite well, with 808 units delivered from 1966–1974, the SW1500 was born into a declining market for purpose-built switchers.
  12. [12]
    No such URL
    **Insufficient relevant content**
  13. [13]
    SW1500 | Locomotives - GATX Corporation
    22 feet. Truck-Rigid Wheel Base 8 feet. Width Over Grab Irons 10 feet, 1/8 inch. Height Above Rails 15 feet. Wheel Diameter 40 inches. Fuel Capacity 600 to ...
  14. [14]
    https://railroad.net/emd-sw1500-switcher-t77842.html
  15. [15]
    https://www.chartertoconductor.com/wp-content/uploads/2019/06/sw1500-om.pdf
  16. [16]
    EMD SW1500 Switcher - RAILROAD.NET
    The standard truck on the SW1500 was the AAR type A switcher truck. The optional truck was the Flexicoil truck.
  17. [17]
    [PDF] OPERATOR'S MANUAL - chartertoconductor
    1 or short hood end of the lead unit, place switch in CONTROL-. LING - COUPLED AT CAB END position. 2. On Intermediate Units. On units operating in between ...
  18. [18]
    WPRM WP 1503 Mobile - Western Pacific RR Museum
    1973 EMD SW1500. Model: SW1500. Builder: Electro-Motive Division (Progress ... Western Pacific 1503 was built in La Grange, Illinois at the Electro ...
  19. [19]
    1930s - ProgressRail
    Ground was broken for the building in La Grange, Illinois on March 27, 1935. 1935 Building La Grange Plant. Electro-Motive No. 511 was a company demonstrator ...
  20. [20]
    EMD SW1500 Order Numbers - TrainWeb.US
    Aug 2, 2025 · SW1500 Order Numbers ; 7190, 02.70, 35297=35302 ; 7285, 04.71, 36855-36860 ; 4557, 05.69, 34972-34975 ; 4585, 08.70 to 09.70, 36487-36490 ...Missing: range production
  21. [21]
    E.M.D. SW 1500 Diesel-Electric Locomotive at Porto Santana
    SW 1500 BoBo, 1500 HP diesel-electric locomotive #5 at Porto Santana. Photo shot in August 30, 1984 by John Kirchner and originally published at the Brazil Page ...
  22. [22]
    VMVX 682 VMV Leasing EMD SW1500 at ... - RailPictures.Net Photo
    May 30, 2023 · High quality photograph of VMV Leasing EMD SW1500 # VMVX 682 at Paducah, Kentucky, USA.<|separator|>
  23. [23]
    Athearn HO ATH29668 DCC Ready EMD SW1500 Locomotive ...
    In stock Free delivery over $599Dual exhaust stacks; Printed numberboards; Fine scale handrails; Signal hoses as appropriate to the prototype road (MU capability was a railroad specified ...
  24. [24]
    [PDF] PENN CENTRAL TRANSPORTATION COMPANY All-time Roster ...
    Jan 29, 2022 · EMD. SW1500. 7355-1 - 50. 02-03/72. 5. 77. 9560-9583. New. CR 9560-9583. ES ... Many units in the 7800-8165 series are seconds and thirds ...
  25. [25]
    Rail - Port of Little Rock
    The Port RR operates a tandem unit with one SW1500 diesel electric EMD locomotive leased from GATX Locomotives and an EMD GP 15-1 locomotive owned by the Port.
  26. [26]
    Locomotives - Age of Steam Roundhouse Museum
    The museum has locomotives such as the Alabama, Tennessee & Northern 2-10-0 No. 401, Buffalo, Rochester & Pittsburgh 0-6-0 No. 152, and Grand Trunk Western 4-8 ...Missing: Conrail 9575 SW1500
  27. [27]
    Kentucky Steam Heritage Equipment
    1100 is an EMD SW1500 "road switcher" capable of producing 1,500 horsepower. These Diesel-electric locomotives were built by GM between 1966-1974 generally ...
  28. [28]
    List of preserved EMD locomotives - Wikipedia
    SW1500. edit. Photograph, Works no. Locomotive, Build date, Model, Former operators, Retire date, Disposition and location, Notes, References. 35938, CSX 1100 ...
  29. [29]
    [PDF] SW1500)/ SSB1200 Switcher Locomotive Repoweri
    Oct 18, 2021 · 1.12 Environmental Requirements This project is being undertaken to provide more efficient and environmentally friendly prime movers on ...
  30. [30]
    EMD SW1500 - Conrail Photo Archive
    The EMD SW1500 was a Conrail switcher, seen in locations like Lansdale, PA, Iona Island, NY, Huntington, MA, and King of Prussia, PA.Missing: predecessors | Show results with:predecessors
  31. [31]
    https://www.trainorders.com/discussion/read.php?2,2198309