Amtrak’s daily Borealis service between St. Paul and Chicago was disrupted Wednesday, with buses replacing trains. The cause of the train cancellation was corrosion of passenger railcars used on the route. Amtrak made the announcement Wednesday morning and said the cancellation also affected its Downeaster, Hiawatha and Cascades service.

Corrosion was found in several railcars used on Amtrak's Borealis — the 7-hour and 24-minute train line from the Twin Cities to the Windy City.

Service of Amtrak's Borealis train connecting Milwaukee to the Twin Cities will be restored without bus substitutions on Friday, the agency said.