The answer would actually be conflict with the native americans
Union Pacific Railroad built the line westward and the Central Pacific Railroad built the line eastward. The first transcontinental railroad basically connected the east and the west of the United States. Central Pacific Railroad merged with Southern Pacific in 1885 and then Union Pacific bought Southern Pacific in 1996. Union Pacific still operates much of the rail from Central Pacific Railroad and Southern Pacific Railroad.
central pacific and union pacific railroad companies
Pacific Railroad ended in 1876.
Pacific Railroad was created in 1849.
Central Pacific Railroad and Union Pacific Railroad Company.
head of the cenral pacific railroad
Western Pacific Railroad was created in 1916.
Western Pacific Railroad ended in 1987.
Southwest Pacific Railroad was created in 1866.
Northern Pacific Railroad ended in 1896.
South Pacific Railroad was created in 1868.