[1] The RailCats started as a member of the Northern League in 2002, operating as a travel team for a season before moving in to U.S. Steel Yard in 2003, where they have played since.

During their time in the Northern League, the RailCats were the only team to ever reach the championship series five years in a row (2005–2009).

On January 23, 2001, the Northern League announced that it had awarded a franchise to Northwest Sports Ventures, LLC.

[2] In June, a limited liability company by the name of Victory Sports Group was officially registered in Missouri, led by Michael A. Tatoian.

The city signed a fifteen-year lease with the team ownership for the future baseball stadium.

In September 2001, the team was officially named the Gary SouthShore RailCats, drawing its name from both the city's deep history of freight lines and the South Shore Line commuter train (visible over the left field wall at the stadium).

The city of Gary paid a financial penalty for failure to complete the stadium on time, which helped finance their season.

In 2002, the RailCats signed a ten-year naming rights agreement with United States Steel Corporation for the stadium.

On October 13, 2010, the RailCats left the Northern League, along with the RedHawks, T-Bones, and the Winnipeg Goldeyes to join the American Association for the 2011 season.

[3] In 2020, the RailCats were not selected as one of six teams to participate in a condensed American Association season as a result of the COVID-19 pandemic.