After the end of the Civil War, Chicago exploded into the meatpacking center of the country.  Railroads allowed Chicago, already in a convenient geographical location, to have the ability to access and ship goods all the way to the East and West coasts of the country.  In 1865, the Union Stock Yard and Transit Company was established and served as the base where millions of pork and cattle were processed and shipped.  Chicago’s Big Three packers – Philip Armour, Gustavus Swift, and Nelson Morris – developed innovative ways to improve the packing industry and were incredibly influential in the success of Chicago’s packing industry.  Ice-cooled rooms and railroad cars, overhead assembly lines for increased ease of moving carcasses, and new ways to preserve the meat processed were invented.  Previously discarded parts of the animals used were discovered to be able to be used to create other products such as glue, gelatin, and fertilizer.  By 1900, the Chicago packing companies had expanded and built plants in other states and employed over a third of the country’s packing employees.