EMD Order #4506 consisted of a pair of SW1500s for shortline operator Minneapolis, Northfield and Southern Railway. Constructed in 1966, the units were equipped with MU capability and were often found running together or with an SW1200.
An EMD SW1500 is a 4-axle diesel switcher locomotive built by General Motors Electro-Motive Division between 1966 and 1974. It is similar in appearance to the EMD SW1000 model, which has a different engine and has one exhaust stack while the SW1500 has two.
Power was provided by an EMD 645E 12-cylinder engine which generated 1,500 horsepower. This locomotive was built on the same common frame as the EMD SW1000, giving it an overall length of 44 feet 8 inches.
The SW1500 featured a bulkier carbody and was a bit heavier from earlier models although its intended use remained the same, working light branch lines or in industrial settings. Many railroads regularly used SW1500s for road freight service.