A regional planning group that includes Rosemont has formally opposed the O'Hare Flyer, a proposed $2.25 billion express train to O'Hare Airport.

The West Central Municipal Conference sent a letter Sept. 11 to O'Hare Flyer leadership stating it cannot support the project until federal, state and local agencies study its potential impact, the Journal & Topics first reported Monday, Sept. 21. The WCMC is an umbrella planning body representing west central suburbs including Rosemont, River Forest, Melrose Park, River Grove and Franklin Park.

The opposition adds to growing pushback against the privately financed proposal, which would send battery-electric trains every 15 minutes along freight corridors through River Forest, Melrose Park and other communities. The Village of River Forest passed its own resolution opposing the project around Sept. 15, ABC7 Chicago reported, citing pedestrian safety, emergency response and environmental concerns.

The route's Rosemont segment would use Canadian National tracks shared by Metra's North Central Service line, a corridor familiar to Park Ridge-area commuters. That Rosemont portion is grade-separated, meaning no new street-level crossings. The WCMC's concern centers on a different stretch.

The proposed route's roughly 7-mile CSX corridor runs mostly at grade through River Forest, Melrose Park, River Grove and Franklin Park. Richard Pellegrino, the WCMC's executive director, warned in his Sept. 11 letter that trains every 15 minutes could choke traffic and slow emergency response in those communities.

"Communities such as River Forest and the surrounding municipalities similarly situated could face increased congestion and longer travel times, as frequent rail closures on major north-south corridors disrupt daily commutes and slow emergency response," Pellegrino wrote.

He also raised concerns about wildlife in the Thatcher Woods forest preserve, which the railroad passes through at ground level.

CSX, the freight railroad whose tracks would carry much of the route, has signed a letter of intent supporting the project. Andy Daly, CSX's senior director of passenger operations, said the company is "pleased to work with the O'Hare Flyer team," according to the Journal & Topics.

The O'Hare Flyer would carry up to 500 passengers per train on a 20-mile route averaging 80 miles per hour, with a projected one-way trip of 15 minutes, according to Capitol News Illinois. The project's backers say it would be entirely privately financed with no government subsidies. Construction could begin as early as 2027, with completion projected for 2032.

Separately, Metra has proposed its own express Chicago-to-O'Hare service on the North Central Service line. Canadian National has balked at paying for additional track infrastructure that more frequent service would require, the Journal & Topics reported.

No Park Ridge official has publicly commented on the O'Hare Flyer proposal. The project still requires approval from the Federal Railroad Administration and the Chicago City Council, though no hearing dates have been set.