Adding a second daily passenger train between St. Paul’s Union Depot and downtown Chicago, a proposal that has been bandied about for many years, would likely cost from $137 million to $169 million. But it’s unclear at this point how the project would be funded, and by whom, says a new study.

A sneak peek of the study’s findings was provided last week to the Ramsey County Regional Railroad Authority by rail planners from the Minnesota Department of Transportation (MnDOT), although the final version has not been made public.

Still, reviews from the board were positive, and several commissioners called for the Legislature to cough up some cash to move the project forward.

“The bottom line is local government has been carrying the water for the last couple of years on this issue,” said Rafael Ortega, Regional Railroad Authority chairman. “We need to push this at the state Legislature.”

The additional service would follow the same path as Amtrak’s Empire Builder long-distance train, which connects Chicago to Seattle or Portland through St. Paul, Red Wing and Winona once a day in both directions.

The idea involves adding another daily train in each direction between Chicago’s Union Station and St. Paul, avoiding travel delays occasionally experienced by the Empire Builder as it travels from the West Coast. A previous study by Amtrak estimated 155,000 passengers would take advantage of expanded service between the two Midwestern cities annually.

The Empire Builder, which chugs east across Washington, Idaho, Montana, North Dakota and western Minnesota, is supposed to leave St. Paul for the Windy City daily at 8 a.m. But the trains share track with freight rail operators in an arrangement that can cause delays.

“It doesn’t always leave at 8 a.m.,” said Frank Loetterle, project manager for MnDOT’s Passenger Rail Office, while addressing the Ramsey board. “The challenge with the eastbound Empire Builder service is that it has traveled hundreds of miles, so it’s not as reliable as it could be.”

The objective is “to have a train leaving St. Paul on time most of the time,” Loetterle added.

The study considers schedules that are roughly four to six hours apart from the Empire Builder’s. Under separate alternatives, eastbound trains could leave St. Paul at 11:47 a.m. or 12:45 p.m., arriving in Chicago at 7:14 p.m. or 8:12 p.m., respectively. Heading west, trains would leave Chicago at 9:25 a.m. or 10:20 a.m., arriving in St. Paul at 4:44 p.m. or 5:39 p.m.

Trains would operate at a maximum speed of 79 miles per hour.

In previous studies, MnDOT and others have pointed out that additional transportation options dovetail with expected population and economic growth along the 418-mile corridor stretching across Wisconsin’s midsection.

“You would be tapping into new audiences, especially if you’re competitive with the drive times” between Chicago and St. Paul, said Brian Nelson, president of All Aboard Minnesota, a rail advocacy group.

“Millennials are shying away from cars; they’re tremendously interested in mass transit,” Nelson said. “Then there are people who don’t want [to] or can’t drive, including families with children and aging baby boomers. This is a nice alternative. It’s part of a balanced transportation plan.”

An informal query on Twitter found many supporters of additional daily service to Chicago, although some expressed skepticism whether it could operate in a timely manner. Some wanted high-speed rail; others said the trip should take five to six hours; and one person called for more bar service on the train. A few others said it’s cheaper to fly.

A 2015 study by Amtrak recommended the proposal proceed with an environmental review and public engagement, which would make the project eligible for federal funding. Next steps for rail supporters now include finding money to pay for such a review.

“Should this service come to pass and current on-time performance continues, this service between the Twin Cities and Chicago should be a high-performing train in terms of reliability,” said Amtrak spokesman Marc Magliari.