Explain how the transcontinental railroad was built by joining two corporations, the Union Pacific and Central Pacific, led by Grenville Dodge and Theodore Judah. Explain that many Chinese immigrants were also hired to work on this project and describe the conditions under which these workers lived and worked. Describe how the railroad benefited the economy and contributed to growth out west. Next, go over how Professor C.F. Dowd divided the days into different time zones, Eastern, Central, Mountain, and Pacific. Finally, discuss how railroad construction also led to an increase in corruption. Have students analyze the political cartoon depicting railroad owner, Jay Gould.