EMD built these NW2 switcher engines from 1939 to 1949. The engine is recognizable by its half-height front radiator grill (which is different from an SW1, which had a large "porch" under the radiator grill), and the flat section on top in front of the cab, just before sloping up (which it shared with some of the early SW1 engines). It has a minimum track radius of 100 feet (19-inch radius in S-scale). Its maximum speed was 60 miles per hour, although it could only do 10mph under maximum tractive force load. It measured 44'5" (13.5m) in length, 14'5" (4.4m) in height, and 10'0" (3.0m) in width. It weighed 248,400lbs (112,672kg). The locomotive has the 567 EMD, 12 cylinder engine, which could produce 1000hp.
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In October 1941, the Pennsylvania Railroad bought NW2 #3909 (shown here; photo from my personal collection). That was the railroad's second diesel engine purchase (it had bought one EMD SW engine before this one). The other NW2s were added in 1945 through 1948. The delay in the purchase of the other NW2s was because EMD was not allowed to produce switcher engines during World War II (it was assigned to only produce road diesel locomotives during the war). In 1942 #3909 was renumbered to #5912. The engines were classified as ES-10, which stands for EMD Switcher with a 1000hp engine. Every single one of the PRR's NW2 engines made it through the merger into the Penn Central (1968), and a good number of them made it to the Conrail era (1976) as well.