 Units rebuilt from SW or SC model locomotives developed 600 or 660 horsepower with the older generators instead of the full 900 horsepower of the SW900.In the early 1960s, the Reading Company sent 14 of their Baldwin VO 1000 model switchers to EMD to have them rebuilt to SW900 specifications.The Reading units retained the Baldwin switcher carbody and were rated at 1000 horsepower by EMD.