A proposed passenger rail line between Minneapolis and Duluth cleared a key hurdle recently after federal regulators determined it will not significantly impact the environment along its 152-mile route.

Now, the Minnesota Department of Transportation (MnDOT) will try to identify federal and state sources to fund the Northern Lights Express, which is expected to cost between $500 million and $600 million.

The line would share track with BNSF Railway freight trains, with service linking Target Field station in Minneapolis with stops in Coon Rapids, Cambridge, Hinckley and Duluth, as well as Superior, Wis. A maintenance facility and a layover operation are being considered for separate sites in Sandstone and Duluth, or both may be located in Duluth.

The Federal Railroad Administration's "Finding of No Significant Impact" means the project can now move forward on other fronts in the development process. The FTA decision was issued on Feb. 20, but not made public by MnDOT until Wednesday.

"It's a significant hurdle because we can now work on getting an agreement with Amtrak, BNSF, and funding for final design and construction," said Frank Loetterle, MnDOT's project manager for the Northern Lights Express.

While early estimates had the federal government paying 80 percent and the state 20 percent, the current funding picture for the project is murky. President Trump has not been entirely supportive of the federal government funding big public transit projects, although some members of Congress may include money for them in the impending federal budget.

"The situation in Washington is unclear," Loetterle said.

While Northern Lights is not technically "high speed" rail — that is, similar to bullet service in Asia and Europe — trains would travel up to 90 miles per hour, averaging about 60 miles per hour.

Amtrak's Empire Builder service, which connects Chicago to Seattle/Portland — through St. Paul's Union Depot — tops out at 79 miles per hour, Loetterle said.

The 2.5-hour trip between Minneapolis and Duluth would cost $30 one way, with some 700,000 to 750,000 people expected to take the train its first year of operation, a figure that is anticipated to increase to 900,000 to 1 million over a 20-year period. Four round trips would be scheduled daily, with Amtrak the likely operator of the service.

MnDOT has said in the past passenger service would begin in 2020, but Loetterle said that estimate is "optimistic."

Amtrak's North Star service was discontinued along the same route in 1985 because of flagging ridership and service problems. But there's been talk about reviving the service at least since the late 1980s.

A series of public hearings were held last spring regarding the project's environmental assessment. According to MnDOT, 85 people attended the hearings, with 21 people expressing support, and four people opposing the project. Other comments focused on topics such as noise, safety and economic development.

Those in favor of the line said it would help connect people to various destinations, while decreasing car use along I-35 between Minneapolis and Duluth. People opposing the project said it would be a waste of public funds and there would be little demand for the service.