https://www.usa.gov/copyrighted-government-workshttps://www.rawpixel.com/image/12290594Edit ImageSaveSaveEditCropCustom TextChicago, Illinois. Cars are uncoupled at the top of the hump and roll down by gravity at an Illinois Central Railroad yard to the classification yards. 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 1103 x 1200 px | 300 dpiLarge JPEG 3217 x 3500 px | 300 dpiBest Quality JPEG 4730 x 5146 px | 300 dpiTIFF 4730 x 5146 px | 300 dpi | 46.45 MBFree DownloadChicago, Illinois. Cars are uncoupled at the top of the hump and roll down by gravity at an Illinois Central Railroad yard to the classification yards. Sourced from the Library of Congress.More