ST. PAUL (AP) — A new Amtrak study says adding a second round-trip between St. Paul and Chicago could prove to be popular.

The Minesota and Wisconsin departments of transportation as well as La Crosse County in Wisconsin asked Amtrak to conduct the study.

The study predicts ridership on a second daily train could exceed 150,000 passengers a year, but Minnesota and Wisconsin would have to subsidize about $6.6 million in operating shortfalls annually.

It says the necessary infrastructure improvements could range from $142 million if the route ends in St. Paul to as high as $257 million if stops are also added in Minneapolis and St. Cloud.

Amtrak's only train now serving the Twin Cities is the once-daily and often late Empire Builder from Chicago via St. Paul to the Pacific Northwest.