The railroad plan is part of Gov. Eric Holcomb's agenda to upgrade the state's infrastructure.
Public meetings will be held in early 2018. A preliminary design will be completed later in the year.
INDOT is hosting three public meetings in mid-September to show new refinements to the Section 6 plan.
Indiana is ranked nearly worst in the nation for most rail crossing fatalities.
Low-income or minority community members who might be impacted by the extension will receive surveys from INDOT.
INDOT says rain has prevented crews from fixing erosion issues along I-69.
How do road crews treat I-69 during bad weather and was an "independent" ISTEP investigation really independent?
INDOT will begin working on design options for the interchange in 2016.
Pence Thursday signed legislation authorizing the release of $400 million for transportation projects.
Karl Browning previously served as INDOT Commissioner from 2006 to 2009 under former Governor Mitch Daniels.