https://www.usa.gov/copyrighted-government-workshttps://www.rawpixel.com/image/12313897Edit ImageSaveSaveEditCropCustom TextChicago, Illinois. Retarder operator in his tower at the hump in the Chicago and Northwestern classification yard. Sourced from the Library of Congress.View public domain image source hereMorePublic DomainFree CCO U.S. Government image for Personal and Business useInfoView CC0 LicenseEditorial use only JPEGTIFFSmall JPEG 1200 x 925 px | 300 dpiLarge JPEG 3500 x 2698 px | 300 dpiBest Quality JPEG 4156 x 3204 px | 300 dpiTIFF 4156 x 3204 px | 300 dpi | 12.73 MBFree DownloadChicago, Illinois. Retarder operator in his tower at the hump in the Chicago and Northwestern classification yard. Sourced from the Library of Congress.More