The Games would involve more than doubling the peak commuter traffic on the Metra commuter rail service. LaHood says his department is ready to help.
"If there's a request to be helpful on transportation issues ? we're ready to do what we can because of the president's commitment to do all that he can to be helpful so that the Olympics come to Chicago," LaHood said.
Metra has said it will borrow trains from other cities if it has to.
The IOC will choose the host city for the 2016 Summer Games next month.