Mayoral challengers, academic experts and aldermen raised caution flags Thursday about Mayor Rahm Emanuel’s choice of visionary billionaire Elon Musk to build a high-speed transit system between downtown and O’Hare Airport.

From environmental impacts, regulatory approvals and financing costs to what lies underground and Musk’s unproven, low-cost, high-speed tunneling technology, experts and critics raised serious questions about whether or not the $1 billion project would ever get built.

“This is a stretch. The regulatory process alone could become a bogeyman … and God knows what you’ll find when you start digging through the city. Who knows if there’s gonna be complications like the Big Dig?” said Joe Schwieterman, director of DePaul University’s Chaddick Institute.

“The risk is this becomes a soap opera — a half-finished project looking for a white knight to save the day. The other risk is the demand. It’s not a slam-dunk that business travelers will instantly pull out their credit cards to pay [$25] to ride.”

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Schwieterman gave the mayor and Musk high marks for dreaming big and aiming high. But he gave the project only a one-in-three chance of ever getting built. And even if it does, he’s afraid Chicago taxpayers could get stuck with at least part of the tab.

That’s even though Emanuel has ruled out even a penny of taxpayer support, and Deputy Mayor Robert Rivkin has argued that the “only real risk to the city” is being left with a “partially-built, essentially cave-in proof sealed tunnel 30-to-60 feet underground in some portion of the city,” which it has already.

“The bigger risk is the city feels compelled to come to the table with financing to fix problems. That could come at the public expense of our transit system,” Schwieterman said.

“If it’s maybe 90 percent done, but they need the city to buy land or they need the city to fix Elston Street because of some construction issue, the city may feel compelled to do that if it wants the project to be finished. That often happens on public works projects where there’s new things you never thought of that have to be done.”

A piece of drilling equipment, pictured on The Boring Company website

On the firm’s website, The Boring Company discusses how it is able to tunnel more cheaply and efficiently by using smaller-diameter equipment. | The Boring Company

Ald. Scott Waguespack (32nd), chairman of the City Council’s Progressive Caucus, demanded a series of public hearings months ago to slow down what he called Emanuel’s pre-election rush to build a transit line to O’Hare.

Waguespack wanted answers he never got about the need to demolish homes and businesses and about the ridership impact on the CTA’s Blue Line before the mayor forged ahead. He also questioned the long-term impact on Chicago taxpayers wondering, “who’s on the hook if this thing goes belly up?”

On Thursday, Waguespack raised all of those questions and more, knowing that, from a bureaucratic standpoint, the express train has already left the station.

“If you’re drilling, there’s definitely gonna be costs, environmental impacts, legal impacts, impacts to both public and private infrastructure and impacts to private and public property that would run from downtown to O’Hare. They kind of act like that doesn’t effect the rest of the world, but it does. You can’t drill in a vacuum,” Waguespack said.

Waguespack accused Emanuel of using his slow-starting Infrastructure Trust as a contracting vehicle to get around the need for public hearings on whether the idea is even worth pursuing.

He was not appeased by Rivkin’s pledge to seek City Council approval of Musk’s final contract once negotiations with the city are completed.

“We should have been having hearings on this to decide what the best idea is. Why not go with the pre-existing rail line at a fraction of the cost? It shouldn’t be the mayor’s idea and ‘We’ll let you guys take a peek at it,’” Waguespack said.

Scott Waguespack

Ald. Scott Waguespack (32nd) has a lot of questions about Mayor Rahm Emanuel’s plan to build a high-speed rail to O’Hare. | Rich Hein/Sun-Times

“You know how those hearings go. Those will be a joke. The decision has already been made — by him, not the public. What’s the point of hearings when he’s making unilateral decisions?”

Whether or not the system ever gets built, Emanuel has created a pre-election diversion akin to former Mayor Richard M. Daley’s failed Olympic bid.

“This announcement — at this time when we have the tragic issue before us about the sexual assault of our children — appears to be more of a distraction and smokescreen,” mayoral challenger Dorothy Brown, the Circuit Court clerk, said in a statement.

Mayoral challenger Lori Lightfoot demanded that Emanuel return the $50,000 contribution he got from Musk in March, 2015.

“The appearance of impropriety is so strong with that, he’s got to give it back,” she said.

Lightfoot said the O’Hare Express project “has potential,” but questions remain about the financial impact on Chicago taxpayers. Nobody “really believes it’s going to be zero,” no matter what the mayor claims, Lightfoot said.

“Once again, we’re chasing the shiny object at a time when people in the neighborhoods are desperate–desperate–for investment,” Lightfoot said.

“When the mayor continues to prioritize these kind of news headline projects at the expense of investment in the neighborhoods, once again, people feel like he doesn’t listen. It fuels the us-against-them mentality and style of government that people think he’s known for.”

Mayoral challenger Garry McCarthy said a 12-minute ride to O’Hare “sounds like a great idea,” but, “I don’t see it happening. Too many things have to fall in place to make it happen,” including “permits, safety hazards, physical obstructions.”