EMD E7 Locomotive Technical Specifications: A Detailed Overview

EMD E7 Locomotive Technical Specifications: A Detailed Overview



The EMD E7 was one of the most iconic diesel-electric locomotives of the mid-20th century, widely used for passenger service in the United States. Built by Electro-Motive Division (EMD) of General Motors from 1945 to 1949, this locomotive was part of the E-series and featured a distinctive bulldog nose design. Below, we explore its technical specifications, highlighting the features that made it a reliable and powerful engine for long-haul passenger trains.

1. General Specifications

  • Builder: Electro-Motive Division (EMD), General Motors
  • Model: E7
  • Type: Diesel-electric
  • Production Years: 1945–1949
  • Total Units Built: 428 (A-units: 324, B-units: 74)
  • Primary Users: Railroads like Pennsylvania Railroad, New York Central, Union Pacific, Southern Railway, and others

2. Mechanical & Powertrain Specifications

Engine & Power Output

  • Prime Mover: Two EMD 567A V12 diesel engines
  • Horsepower: 2,000 HP (1,000 HP per engine)
  • RPM Range: 800 RPM (maximum)
  • Aspiration: Roots-type supercharger
  • Fuel Capacity: 1,200–1,500 gallons (varied by railroad)
  • Lube Oil Capacity: Approximately 300 gallons

Traction & Wheel Arrangement

  • Wheel Configuration: A1A-A1A
    • Meaning: Each truck (bogie) had three axles, with the outer two powered and the middle one unpowered.
  • Traction Motors: Four EMD D7
  • Gear Ratio: 52:15
  • Maximum Speed: 85–100 mph (137–161 km/h)
  • Tractive Effort: 31,000 lbf (starting)

3. Electrical System

  • Generator: EMD D4 DC generator
  • Traction Motors: DC-powered
  • Control System: Electro-pneumatic control

4. Dimensions & Weight

  • Length: 71 ft 1 in (21.67 m)
  • Width: 10 ft 7 in (3.23 m)
  • Height: 14 ft 7 in (4.44 m)
  • Weight: 315,000 lbs (143,000 kg)

5. Notable Features

  • Streamlined design: The E7 had an aerodynamic body with a distinctive bulldog nose, improving airflow efficiency.
  • Dual-engine configuration: Unlike single-engine locomotives, the E7 had two 567A V12 engines, offering redundancy and higher reliability.
  • Passenger service optimization: It was designed specifically for long-haul passenger trains, providing smooth and efficient operation.
  • Stainless steel or painted finish: Railroads customized their units with different liveries to match their branding.

6. Legacy of the EMD E7

The E7 played a crucial role in transitioning American railroads from steam to diesel power. It was eventually replaced by newer EMD models like the E8 and E9, but some units have been preserved in railway museums.

One of the most famous preserved E7s is Pennsylvania Railroad #5901, displayed at the Railroad Museum of Pennsylvania.

Conclusion

The EMD E7 locomotive was a groundbreaking diesel-electric locomotive that defined passenger rail travel in the post-war era. With its powerful engines, streamlined design, and reliable performance, it remained a favorite among railroads and railfans alike.

Would you like to explore more about surviving E7 locomotives or their operational history? Let us know in the comments!

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