After the railroad reached Waterloo in 1861, the town would never be the same. Then businesses in Waterloo could send products anywhere the rail lines stretched.

The Illinois Central Railroad (ICRR) was the most important railroad company in Waterloo. It linked the city to Chicago and to the nation when it was built in 1861.

In 1870, the ICRR expanded and built repair shops in the city.

By 1900 the railroad employed over 2,000 workers.

Another important railroad company was the Chicago Great Western.

The Chicago Great Western railroad formed a diagonal line that connected Kansas City with St. Paul. As it was built from Des Moines to Waterloo in 1884, it crossed the Illinois Central tracks near Waterloo and built repair shops in nearby Oelwein.

Other important railroad events in Waterloo and the Cedar Valley include:

• Dubuque and Pacific Railroad, first railroad in area connecting Waterloo and Cedar Falls with Dubuque on the Mississippi River
• Cedar Falls and Minnesota Railroad, providing transportation strength to industries in Cedar Falls
• Illinois Central, took over the line of the previous two companies, providing greater integration of service
• Wisconsin, Iowa, and Nebraska Railroad, spurred the growth of Hudson
• Chicago Great Western Railroad, connected Waterloo directly to Chicago, spurring growth in industry, particularly livestock processing and canning
• Rock Island Railroad, connecting towns along the Cedar River