The Denver Rock Island Railroad has been working these tracks since 2005 when the DRIR acquired the Stock Yard Lead from the Union Pacific Railroad. Although still functional, the tracks in this area have been around since the early 1900's, when the development of the nearby Denver Stock Yard Company created the demand for trainloads of cattle, sheep, and pigs that were delivered via livestock cars seven days a week, 24 hours a day to be sold and traded in the active marketplace. The activity in the crowded yards was comparable to what can be found today at the New York Stock Exchange. With all that activity it was not long before packing plants and other industries sprouted in the area. One large packing plant operated by Armour & Company and built in 1917 dominated the area, until 1987 when most of the facility was demolished, leaving only one office building and the old water tower as reminders of Denver's heyday of livestock trading.