Baltimore and Ohio No. 9624 TR4 cow-calf set at Riverside Yard, Baltimore, in 1969.
(Roger Puta, courtesy Marty Bernard, Public domain, via Wikimedia Commons)
EMD SW7 DIESEL-ELECTRIC LOCOMOTIVE
The EMD SW7 was a diesel switcher locomotive built by General Motors Electro-Motive Division between October 1949 and January 1951. It was powered by a 1,200 horsepower (895 kW)12-567A engine. The SW7 replaced the earlier 1,000 horsepower NW2 switcher in EMD's catalog. A total of 489 SW7 locomotives were produced. The majority of the SW7s were built by EMD Plant No. 3 in Cleveland, Ohio. In addition, 15 TR4 cow-calf paired sets were produced.
SW7 production was discontinued in 1951 in favor of the new SW9.
Southern 8202 at the Southeastern Railway Museum, Duluth, GA.
(Josh Hallett from Winter Haven, FL, USA, CC BY-SA 2.0 <https://creativecommons.org/licenses/by-sa/2.0>, via Wikimedia Commons)
Original buyers
| Railroad | Quantity | Road numbers |
|---|---|---|
| Arkansas and Louisiana Missouri Railway | 1 | 11 |
| Atlantic Coast Line Railroad | 9 | 643–651 |
| Central Railroad of New Jersey | 4 | 1080–1083 |
| Charleston and Western Carolina Railway | 2 | 800–801 |
| Chesapeake and Ohio Railway | 26 | 5214–5239 |
| Chicago and Eastern Illinois Railroad | 6 | 126–131 |
| Chicago and Eastern Illinois (Chicago Heights Terminal and Transfer Railroad) | 2 | 132–133 |
| Chicago and Illinois Western Railroad | 3 | 101–103 |
| Chicago, Burlington and Quincy Railroad | 20 | 9249–9268 |
| Chicago, Milwaukee, St. Paul and Pacific Railroad | 1 | 1646 |
| Clinchfield Railroad | 6 | 350–355 |
| Colorado and Southern Railway | 1 | 154 |
| Conemaugh and Black Lick Railroad | 15 | 103–117 |
| Cornwall Railroad | 3 | 120–122 |
| Detroit and Toledo Shore Line Railroad | 3 | 116–118 |
| Detroit Terminal Railroad | 1 | 116 |
| Detroit, Toledo and Ironton Railroad | 5 | 920–924 |
| Erie Railroad | 6 | 428–433 |
| Great Northern Railway | 11 | 163–170, 11–13 |
| Illinois Central Railroad | 50 | 9300–9319, 9400–9429 |
| Kansas City Southern Railway | 10 | 1300–1309 |
| Kansas City Southern Railway (Louisiana and Arkansas Railway) | 6 | 1310–1315 |
| Lakeside and Marblehead Railroad | 1 | 12 |
| Lehigh Valley Railroad | 5 | 220–224 |
| Louisiana Midland Railway | 1 | 10 |
| Louisville and Nashville Railroad | 22 | 2245–2266 |
| Maine Central Railroad | 3 | 331–333 |
| Missouri Pacific Railroad | 5 | 9142–9146 |
| Monessen Southwestern Railway | 1 | 21 |
| Montour Railroad | 1 | 72 |
| Nashville, Chattanooga and St. Louis Railway | 10 | 24–33 |
| New York Central Railroad | 34 | 8851–8855, 8880–8897, 8911–8921 |
| New York Central (Indiana Harbor Belt Railroad) | 40 | 8835–8850, 8856–8879 |
| New York Central (Chicago River and Indiana Railroad) | 6 | 8898–8903 |
| New York Central (Peoria and Eastern Railway) | 7 | 8904–8910 |
| New York, Chicago and St. Louis Railroad (“Nickel Plate Road”) | 3 | 230–232 |
| Northern Pacific Railway | 8 | 107–114 |
| Pennsylvania Railroad | 48 | 8861–8868, 8871–8872, 9358–9395 |
| Peoria and Pekin Union Railway | 5 | 406–410 |
| Phelps Dodge Corporation (New Cornelia Branch Mine) | 1 | 6 |
| Philadelphia, Bethlehem and New England Railroad | 4 | 31–34 |
| River Terminal Railway | 2 | 61–62 |
| Southern Railway (Alabama Great Southern Railroad) | 5 | 6505–6509 |
| Southern Railway (Cincinnati, New Orleans and Texas Pacific Railway) | 14 | 6060–6073 |
| Southern Railway (Georgia Southern and Florida Railway) | 4 | 8200–8203 |
| Southern Railway (New Orleans and North Eastern Railway) | 12 | 6852–6863 |
| St. Louis Southwestern Railway (“Cotton Belt”) | 4 | 1054–1057 |
| St. Louis-San Francisco Railway (“Frisco”) | 5 | 300–304 |
| Texas and Pacific Railway | 4 | 1020–1023 |
| Union Pacific Railroad | 25 | 1800–1824 |
| Union Railroad | 4 | 571–574 |
| Wabash Railroad | 8 | 355–362 |
| Weyerhaueser Timber Company | 2 | 300–301 |
| Woodward Iron Company | 2 | 50–51 |
| Youngstown and Southern Railway | 2 | 70–71 |
| Total | 489 |
Belt Railway of Chicago 504 and 512 in Clearing Yard, Chicago, IL in January 1985.
(Roger Puta, courtesy Marty Bernard, railfan 44, Public domain, via Wikimedia Commons)
TR4
| Railroad | Quantity | Road numbers |
|---|---|---|
| Atchison, Topeka and Santa Fe Railway | 2 sets | 2418,A–2419,A |
| Belt Railway of Chicago | 5 sets | 502AB–506AB |
| Chesapeake and Ohio Railway | 2 sets | 6001AB–6002AB |
| Chicago, Milwaukee, St. Paul and Pacific Railroad | 6 sets | 2001AB–2006AB |
Maine Central EMD SW7 331 at Bangor, Maine, November 14, 1980. Photographer: J R Quinn.
(Craig Garver, Public domain, https://www.flickr.com/photos/digitalrailartist/51003915222/)
Overview
Type and origin
Power type: Diesel-electric
Builder: General Motors Electro-Motive Division (EMD)
Model: SW7, TR4
Build date: October 1949 – January 1951
Total produced SW7: 489
Total produced TR4: 15 sets
Specifications
Configuration:
• AAR B-B
• UIC Bo′Bo′
Gauge: 4 ft 8+1⁄2 in (1,435 mm) standard gauge
Prime mover EMD 12-567BA
Engine type: V12 diesel
Aspiration: Roots-type supercharger
Cylinders: 12
Performance figures
Power output: 1,200 hp (895 kW)
