و آر ایل:http://www.americanyawp.com/text/wp-content/uploads/29-chicago-burlington-quincy-rail-road-circa-1880.jpg
و آر ایل:https://courses.lumenlearning.com/sanjacinto-atdcoursereview-ushistory2-1/chapter/western-economic-expansion-railroads-and-cattle-2/