What were EMD E-units, and what was their primary purpose?

EMD E-units were a series of diesel locomotives specifically designed and manufactured by General Motors Electro-Motive Division (EMD) for use in passenger streamliner trains. Production of these locomotives occurred from May 1937 to December 1963, with all final assembly taking place in La Grange, Illinois.

What is the origin of the 'E' designation in EMD E-units?

The 'E' designation in EMD E-units originally signified the locomotive's horsepower rating. Specifically, it stood for eighteen hundred horsepower (1800 hp), which was the power output of the earliest models in the series. This designation was retained for subsequent models even as their power increased.

What were the predecessors to the EMD E-units, and how did they differ?

The predecessors to the EMD E-units were the EMC 1800 hp B-B locomotives built in 1935. These earlier locomotives shared similar power and mechanical layouts but were housed in boxcab bodies and utilized AAR type B two-axle trucks, distinguishing them from the E-units' design.

How did the EMC TA model relate to the E-units, and why is it not considered part of the E-unit series?

The EMC TA model, introduced in 1937, shared carbody styling with the E-units but was mechanically distinct. It was a single-engined unit producing 1,200 hp and used B-B trucks, whereas the E-units were twin-engined and featured A1A-A1A trucks. Therefore, the TA is not classified as part of the E-unit series.

What was the significance of the twin-engine configuration in EMD E-units?

The twin-engine configuration in EMD E-units was crucial for maximizing power output and ensuring operational reliability. If one of the Winton Diesel engines failed, the other could still power the train, albeit at a reduced speed, preventing a complete loss of motive power, which was a significant advantage over single-engine designs.

What is the difference between an 'A unit' and a 'B unit' in the context of EMD E-units?

EMD E-units were available as 'A units' or lead units, which were equipped with a cab for the crew to operate the locomotive. 'B units,' also known as booster units, were cabless and were designed to be controlled remotely by an A unit. While B units contained hostler controls, they could not be operated independently on the main line.

How were multiple EMD E-unit locomotives controlled when operating together in a train consist?

Locomotive units within an EMD E-unit consist were linked together via cables. This system allowed the crew in the lead A unit to control the operation of all trailing units, enabling efficient management of longer and more powerful train sets.

What were the common configurations for EMD E-units purchased by railroads?

Railroads typically purchased EMD E-units in sets such as 'ABA' configurations, which involved two cab-equipped A units positioned at opposite ends of a cabless B unit, or 'ABB' configurations, consisting of a single A unit paired with two B units. These configurations provided operational flexibility and efficiency.

What advantage did the ABA configuration offer for locomotive consists?

The ABA configuration offered a significant operational advantage because the locomotive consist did not need to be turned around to change the direction of travel. This flexibility streamlined operations, especially on routes where turning facilities were limited.

What were the primary engines used in the earliest EMD E-unit models (EA/EB through E2)?

The initial EMD E-unit models, including the EA/EB, E1, and E2, were powered by twin Winton 201-A V-12 engines. Each engine produced 900 horsepower, resulting in a total output of 1,800 horsepower per locomotive unit. These engines were developed through a partnership between General Motors and Winton.

What were the limitations of the Winton 201-A engine in railroad service?

The Winton 201-A engine, while innovative for its time, was not ideally suited for the sustained full-throttle operation often required in railroad service. It was a compromise between marine and locomotive applications, leading to potential reliability issues and the need for frequent heavy repairs, sometimes performed en route.

What engine replaced the Winton 201-A in later EMD E-unit models, and why was it significant?

The EMD 567 series engine replaced the Winton 201-A starting with the E3 model. This engine was specifically designed by EMD for locomotive applications and proved to be significantly more reliable and durable, reportedly offering a five-fold improvement in piston life compared to its predecessor.

How was the EMD 567 engine named, and what were its key characteristics?

The EMD 567 engine was named after its displacement of 567 cubic inches per cylinder. It was a two-stroke diesel engine featuring mechanical aspiration and a V-type configuration (specifically, a 45-degree V). This engine became the standard prime mover for EMD locomotives for many years.

What was the horsepower progression of the EMD 567 engine across different E-unit models?

The 12V-567 engine used in the E3 through E6 models developed 1,000 horsepower. The E7 model utilized the 12V-567A, also rated at 1,000 hp. The E8 featured the improved 567B engine, producing 1,125 hp per engine, and the final E9 model used the 567C engine, rated at 1,200 hp per engine.

How did the styling of the EMD E-unit noses evolve across different models?

The styling of E-unit noses varied significantly. Early models like the EA and E1 had sloping noses with recessed headlights. The E2 introduced a distinctive bulbous 'bulldog nose.' Models E3 through E6 featured a sloping nose but with a protruding headlight, while the E7 through E9 adopted a less sloped, more vertical nose design, similar to that of the EMD F-units.

What made the EMD E5 units unique in terms of their appearance?

The EMD E5 units were unique because they were clad entirely in stainless steel and featured fluted lower carbody sides. This distinctive appearance was specifically designed for the Chicago, Burlington and Quincy Railroad to complement the aesthetic of their famous Zephyr streamliner trains.

What were some notable 'other changes' or improvements introduced on later EMD E-unit models?

Beyond engine upgrades, later EMD E-unit models incorporated other significant improvements. For instance, the E8 model was the first to feature electric cooling fans and offered dynamic braking as an optional feature, enhancing performance and operational capabilities.

How did the side windows and grilles differ among various EMD E-unit models?

The design of side windows and grilles evolved across EMD E-unit models. Windows were half-rounded on the EA/EB, square on the E1, round on the E2, square again on most E3 through E7 units, and returned to rounded portholes on the E8 and E9. The E8 also introduced distinctive one-piece stamped stainless-steel side grilles running below the roofline, although these were often retrofitted to earlier units.

What is the total number of EMD E-units produced across all models?

In total, EMD produced 1,171 A units and 254 B units, bringing the grand total of EMD E-units manufactured to 1,425 locomotives.

Which EMD E-unit model achieved the highest production numbers and became the best seller?

The EMD E7, introduced in 1945, was the most successful model in the E-unit series, becoming the best-selling E-unit with 428 A units and 82 B units produced.

What were the horsepower ratings for the final EMD E-unit models, the E8 and E9?

The EMD E8 models were powered by 12-V567B engines, providing a total output of 2,250 horsepower per unit. The subsequent E9 models featured uprated 12V-567C engines, delivering a total of 2,400 horsepower per unit.

What information is provided by the 'Notes' section associated with the EMD E-unit models table?

The 'Notes' section clarifies the specific railroads that ordered particular E-unit models and details the configurations in which they were delivered, such as the number of A units, B units, or specific set arrangements like ABB. This provides context on customer orders and distribution.

How many EMD E7 A and B units were produced?

A total of 428 EMD E7 A units and 82 EMD E7 B units were manufactured.

How many EMD E8 A and B units were produced?

EMD produced 450 EMD E8 A units and 46 EMD E8 B units.

How many EMD E9 A and B units were produced?

Production figures for the EMD E9 include 100 A units and 44 B units.

What is the significance of the 'More Footnotes Needed' template at the beginning of the article?

The 'More Footnotes Needed' template indicates that while the article contains general references, it lacks sufficient inline citations to support specific factual claims. It serves as a request for editors to improve the article's reliability by adding precise citations.

What does the image caption 'Southern Pacific EMD E7s on the Shasta Daylight in 1949' describe?

This caption describes a photograph taken in 1949, showing EMD E7 diesel locomotives operated by the Southern Pacific railroad pulling the Shasta Daylight passenger train.

What does the image caption 'CB&Q 9911A, an EMD E5, operating at the Illinois Railway Museum, July 18, 2004' describe?

The caption refers to an EMD E5 locomotive, specifically Chicago, Burlington and Quincy (CB&Q) unit number 9911A. It indicates that this locomotive was operational at the Illinois Railway Museum on July 18, 2004.

What was the production timeframe for EMD E-units?

EMD E-units were produced over a significant period, starting in May 1937 and concluding in December 1963.

What was the horsepower of the earliest EMD E-unit models?

The earliest EMD E-unit models, such as the EA/EB, E1, and E2, were powered by twin Winton 201-A engines, each rated at 900 horsepower, for a combined total of 1,800 horsepower per unit.

What was the primary prime mover used in EMD E-units from the E3 model onwards?

From the E3 model onwards, EMD E-units utilized the purpose-designed EMD 567 series engine. This engine was a two-stroke diesel engine available in V12 configurations and became a standard for EMD locomotives.

What was the displacement of the EMD 567 engine per cylinder?

The EMD 567 engine was named for its displacement of 567 cubic inches per cylinder.

How did the EMD 567 engine improve upon the earlier Winton 201-A engine?

The EMD 567 engine offered greater reliability and longevity for locomotive use compared to the Winton 201-A. It featured a larger displacement per cylinder and operated at a higher RPM, contributing to increased power output and improved piston life.

What was the horsepower rating of the EMD 567B engine used in the E8 models?

The EMD 567B engine, used in the E8 models, produced 1,125 horsepower per engine, for a total of 2,250 horsepower in the E8 locomotive unit.

What was the horsepower rating of the EMD 567C engine used in the E9 models?

The EMD 567C engine, utilized in the E9 models, was rated at 1,200 horsepower per engine, resulting in a total output of 2,400 horsepower for the E9 locomotive unit.

What was the primary purpose of the center axle on the Blomberg A1A-A1A trucks?

The center axle on the Blomberg A1A-A1A trucks was unpowered. Its main function was to help support the locomotive's weight and contribute to stability, while the traction motors were located on the outer, powered axles.

What does the 'navbox' template typically represent in a Wikipedia article like this one?

The 'navbox' template, often found at the bottom of Wikipedia articles, serves as a navigational tool. It provides links to related topics, such as other locomotive models or categories, allowing readers to easily explore connected subjects within the same domain.

Which EMD E-unit model was specifically built for the Chicago, Burlington and Quincy Railroad and featured a unique stainless steel construction?

The EMD E5 model was uniquely constructed for the Chicago, Burlington and Quincy Railroad. These locomotives were clad in stainless steel with fluted sides to match the railroad's distinctive Zephyr streamliner trains.

What is the Illinois Railway Museum's significance regarding EMD E-units?

The Illinois Railway Museum in Union, Illinois, houses one of the largest collections of operable and preserved EMD E-units. Notable examples include the CB&Q E5 9911A and WSOR 102, which is one of the few remaining operational B units.

Which EMD E-unit model is preserved at the Southeastern Railway Museum in Duluth, Georgia?

The Southeastern Railway Museum in Duluth, Georgia, preserves Southern Railway #6901, an EMD E8 model that was once used to power the famous Crescent train.

How did EMD E-units contribute to the viability of diesel power in passenger service?

As standardized, mass-produced locomotives built with economies of scale in mind, EMD E-units demonstrated the capability and reliability of diesel power for full-sized passenger consists. This marked a significant threshold in diesel locomotives replacing steam engines in passenger service.

What was the total number of EMD E-units produced, combining both A and B units?

Across all models, the total production of EMD E-units, encompassing both cab-equipped A units and cabless B units, reached 1,425 locomotives.

Emd E-unit Wiki: EMD E-Units: Architects of the Streamliner Era

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Defining the Streamliner

The Dawn of Diesel Passenger Service

The EMD E-units represent a pivotal series of diesel-electric passenger train locomotives manufactured by the Electro-Motive Division (EMD) of General Motors, and its predecessor, Electro-Motive Corporation (EMC). Produced from May 1937 to December 1963, these locomotives were instrumental in the transition from steam to diesel power for mainline passenger service across North America. The "E" designation initially signified their 1,800 horsepower rating, a substantial output for the era, though subsequent models offered increased power.

Streamlined Aesthetics and Performance

Designed with the distinctive "streamliner" aesthetic, E-units featured integrated carbody construction and often sported polished stainless steel or painted fluted sides, complementing the sleek designs of the passenger cars they pulled. Mechanically, they standardized the use of twin diesel engines, providing redundancy and high power output crucial for maintaining schedules on long-distance routes. This configuration allowed for efficient operation and marked a significant advancement in motive power technology.

Lineage and Relationships

The E-units evolved from earlier EMC experimental models like the 1800 hp B-B units and the TA model. While sharing design principles, the TA was a single-engined unit. The E-units' twin-engine, A1A-A1A truck configuration became a hallmark. They are often discussed alongside the EMD F-units, which shared similar prime movers and construction but were primarily designed for freight service with their characteristic "bulldog nose" and cab structure.

Evolution of Power and Design

Early Innovations (EA/EB, E1, E2)

The foundational E-unit models, including the EA/EB, E1, and E2, were powered by twin 900 hp Winton 201A V-12 engines. These early units established the core mechanical layout and the A1A-A1A truck design. Styling varied, with the EA and E1 featuring sloped noses and recessed headlights, while the E2 adopted a more pronounced "bulldog" nose. These models laid the groundwork for future developments, demonstrating the viability of diesel power for demanding passenger services.

The EMD 567 Engine Era (E3-E9)

A significant technological leap occurred with the introduction of the EMD 567 series engine, beginning with the E3 model. This purpose-built two-stroke diesel engine offered improved reliability, power, and efficiency compared to the earlier Winton units. The 567 engine family, named for its 567 cubic inches displacement per cylinder, powered all subsequent E-units through the E9. Power output progressively increased across these models, culminating in the 2,400 hp E9.

Styling Refinements

Throughout their production run, E-units underwent stylistic evolution. Early models featured distinct nose designs, while later units, particularly the E7 through E9, adopted a more vertical, F-unit-inspired "bulldog nose." The E5 model stood out with its full stainless steel cladding, designed to match the aesthetic of the Chicago, Burlington and Quincy Railroad's Zephyr trains. Many locomotives were also updated with features like Farr stainless steel grilles and revised window arrangements over their service lives.

The Heartbeat: Powerplants

Winton 201-A: The Pioneer Engine

The earliest E-units (EA/EB, E1, E2) utilized the Winton 201-A V-12 engine, rated at 900 hp per engine, for a total of 1,800 hp per locomotive unit. While groundbreaking for its power-to-weight ratio, the 201-A was not ideally suited for the sustained full-throttle operation typical of railroad service. This often necessitated in-transit repairs on one engine while the other maintained reduced speed, highlighting the need for a more robust design.

EMD 567 Series: The Workhorse

The introduction of the EMD 567 engine marked a significant advancement. This two-stroke, 45-degree V-type engine, named for its 567 cubic inch displacement per cylinder, was specifically engineered for locomotive applications. Its enhanced reliability and performance characteristics, including greater displacement and higher RPM capability, made it the standard for all subsequent E-units (E3 through E9). The 12V-567 variants evolved through A, B, and C configurations, progressively increasing horsepower from 1,000 hp to 1,200 hp per engine.

Power Progression

The power output of E-units saw a steady increase throughout their development:

EA/EB, E1, E2: 1,800 hp total (2 x 900 hp Winton 201-A)
E3, E4, E5, E6: 2,000 hp total (2 x 1,000 hp 12V-567)
E7: 2,000 hp total (2 x 1,000 hp 12V-567A)
E8: 2,250 hp total (2 x 1,125 hp 12V-567B)
E9: 2,400 hp total (2 x 1,200 hp 12V-567C)

This increase in horsepower enabled E-units to handle heavier trains and maintain faster schedules, solidifying diesel's dominance in passenger rail.

Underpinnings: Blomberg Trucks

The A1A-A1A Design

All EMD E-units featured a specialized passenger truck design developed by engineer Martin Blomberg. This configuration, known as A1A-A1A, utilized three axles per truck. The outer two axles were powered by traction motors, while the center axle was unpowered. This arrangement was chosen to distribute weight more effectively, reducing track stress while providing ample support for the locomotive's heavy power plant and ensuring a smooth ride for passengers.

Engineering Excellence

The Blomberg A1A-A1A trucks incorporated features like outside spring hangers, which improved cushioning against lateral motion. This design philosophy, also seen in the widely adopted Blomberg B trucks used on F-units, prioritized ride quality and durability. The consistent application and minimal changes to this truck design over the E-unit's production life attest to its engineering success and suitability for high-speed passenger service.

Power Transmission

Each A1A-A1A truck housed two direct current generators that powered four traction motors in total – two per truck. This robust electrical system was essential for delivering the substantial power generated by the twin diesel engines to the rails, enabling the E-units to achieve and maintain the high speeds required for efficient passenger train operation.

Aesthetic Evolution

Nose Designs: From Slant to Bulldog

The visual identity of the E-units evolved significantly. Early models like the EA/EB and E1 featured a distinctive sloped "slant nose" with recessed headlights. The E2 introduced a more rounded, bulbous "bulldog nose." Subsequent models, starting with the E7, adopted a more upright, F-unit-style "bulldog nose." These changes reflected both functional considerations and the prevailing design trends of the era.

Streamliner Accents

Beyond the nose, E-units incorporated numerous styling elements that defined the streamliner era. Many models featured fluted sides, often clad in polished stainless steel, particularly the iconic E5 units built for the Chicago, Burlington and Quincy Railroad. Later models often incorporated continuous side grilles, such as the Farr stainless steel grilles introduced with the E8, enhancing the locomotive's sleek, integrated appearance.

Window Variations

Window configurations also varied across E-unit models and customer specifications. Early units might have had half-rounded or square side windows, while later models like the E8 and E9 often featured characteristic "porthole" windows. Over time, many locomotives were retrofitted or rebuilt, leading to a mix of styling elements within specific classes.

Model Compendium

Key E-Unit Specifications

The following table details the primary models within the EMD E-unit series, highlighting their development milestones, engine specifications, and production figures.

Model Designation	Build Year	Total Produced	AAR Wheel Arrangement	Prime Mover	Power Output
EA/EB	1937–1938	6 A units, 6 B units	A1A-A1A	Winton 201-A	1,800 hp (1,300 kW)
E1	1937–1938	8 A units, 3 B units	A1A-A1A	Winton 201-A	1,800 hp (1,300 kW)
E2	1937	2 A units, 4 B units	A1A-A1A	Winton 201-A	1,800 hp (1,300 kW)
E3	1938–1940	17 A units, 2 B units	A1A-A1A	EMD 567	2,000 hp (1,490 kW)
E4	1938–1939	14 A units, 5 B units	A1A-A1A	EMD 567	2,000 hp (1,490 kW)
E5	1940–1941	11 A units, 5 B units	A1A-A1A	EMD 567	2,000 hp (1,490 kW)
E6	1939–1942	91 A units, 26 B units	A1A-A1A	EMD 567	2,000 hp (1,490 kW)
E7	1945–1949	428 A units, 82 B units	A1A-A1A	EMD 567A	2,000 hp (1,490 kW)
E8	1949–1954	450 A units, 46 B units	A1A-A1A	EMD 567B	2,250 hp (1,678 kW)
E9	1954–1964	100 A units, 44 B units	A1A-A1A	EMD 567C	2,400 hp (1,790 kW)

Enduring Presence

Preservation and Operation

A significant number of EMD E-units have been preserved, with many maintained in operational condition. These locomotives are often utilized for special passenger excursions, management inspection trains, and heritage rail operations. Their continued presence allows enthusiasts and the public to experience the power and elegance of these classic machines firsthand.

Notable Collections

Museums and heritage railways across North America house notable E-unit collections. The Illinois Railway Museum, for instance, boasts one of the largest assemblages of operable and preserved E-units, including the unique CB&Q E5 9911A and a rare operable B unit. The Southeastern Railway Museum in Duluth, Georgia, preserves Southern Railway E8 #6901, a locomotive that once powered the famed Southern Crescent.

Continued Relevance

While no longer in regular mainline passenger service, the surviving E-units serve as vital links to a significant era in railroad history. Their preservation ensures that the engineering ingenuity and iconic styling of the EMD E-units continue to inspire and educate future generations of rail enthusiasts and engineers.

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References

For the Baltimore and Ohio Railroad.

For the Atchison, Topeka and Santa Fe Railway.

For the Seaboard Air Line.

For the Chicago, Burlington and Quincy Railroad.

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This document has been generated by an Artificial Intelligence model, drawing information exclusively from the provided source text, which is based on publicly available data from Wikipedia. It is intended solely for educational and informational purposes.

This content does not constitute professional engineering, historical, or technical advice. The information presented is a synthesized overview and may not encompass all nuances or the most current data. Users should consult official technical documentation, historical archives, and qualified experts for definitive information or specific applications. Reliance on this content is at the user's own risk.

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EMD E-Units: Architects of the Streamliner Era

💡 Dive in with Flashcard Learning! 💡

Defining the Streamliner 🚂

✨ The Dawn of Diesel Passenger Service

🚀 Streamlined Aesthetics and Performance

🔗 Lineage and Relationships

Evolution of Power and Design ⚙️

📜 Early Innovations (EA/EB, E1, E2)

💡 The EMD 567 Engine Era (E3-E9)

🎨 Styling Refinements

The Heartbeat: Powerplants ⛽

⚙️ Winton 201-A: The Pioneer Engine

⚡ EMD 567 Series: The Workhorse

📊 Power Progression

Underpinnings: Blomberg Trucks 🔩

🛤️ The A1A-A1A Design

🔧 Engineering Excellence

🔄 Power Transmission

Aesthetic Evolution 🎨

👃 Nose Designs: From Slant to Bulldog

✨ Streamliner Accents

🪟 Window Variations

Model Compendium 📊

📜 Key E-Unit Specifications

Enduring Presence 🏛️

🌟 Preservation and Operation

🏛️ Notable Collections

🚂 Continued Relevance

Teacher's Corner 🧑‍🏫

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📜 References

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Important Context ⚠️

📜 Educational Disclaimer

Dive in with Flashcard Learning!

Defining the Streamliner

The Dawn of Diesel Passenger Service

Streamlined Aesthetics and Performance

Lineage and Relationships

Evolution of Power and Design

Early Innovations (EA/EB, E1, E2)

The EMD 567 Engine Era (E3-E9)

Styling Refinements

The Heartbeat: Powerplants

Winton 201-A: The Pioneer Engine

EMD 567 Series: The Workhorse

Power Progression

Underpinnings: Blomberg Trucks

The A1A-A1A Design

Engineering Excellence

Power Transmission

Aesthetic Evolution

Nose Designs: From Slant to Bulldog

Streamliner Accents

Window Variations

Model Compendium

Key E-Unit Specifications

Enduring Presence

Preservation and Operation

Notable Collections

Continued Relevance

Teacher's Corner

True or False?

Test Your Knowledge!

Gamer's Corner

Discover other topics to study!

References

Feedback & Support

Important Context

Educational Disclaimer