An express train from downtown to O’Hare International Airport could be built on a second level of track above the CTA’s Blue Line, providing a first-of-its-kind “double-decker” service down the middle of the Kennedy Expressway, Chicago Aviation Commissioner Ginger Evans said Wednesday.

In a wide-ranging interview with the Chicago Sun-Times, Mayor Rahm Emanuel’s new aviation chief bubbled with ideas about how to improve service to and at O’Hare — an airport she described as “busting at the seams” and having “a lot of needs.” She also dismissed pursuing any privatization of Midway Airport as running down a “blind alley.”

Ideas for O’Hare included relocating concessions inside domestic terminals to a second-floor “mall” area; adding more gates at O’Hare, but not more terminals; and sticking with the six parallel east-west runways originally envisioned under the $8.7 billion O’Hare Modernization Program.

When it came to solving record complaints about O’Hare jet noise, Evans had no immediate answers, although she said she is ready to listen.

Evans said she will meet personally with the Fair Allocation in Runways coalition, as promised under a legislative resolution, to hear their ideas. But she could not yet say whether O’Hare should keep all four of its diagonal runways open to spread out air traffic more evenly, as FAIR has demanded.

In addition, Evans said Mayor Rahm Emanuel would not attend the three planned FAIR meetings — something legislators had to step in to finally achieve.

FAIR leader Jac Charlier said Wednesday “there are no surrogates for the mayor” on the jet noise issue and, after extending more than a dozen invitations to Emanuel, he expects the mayor to attend.

“This is my area of technical expertise. This is the reason I was hired,’’ Evans explained. “I will listen and evaluate.”

Emanuel has made high-speed rail to O’Hare one of the top priorities of his second-term agenda. During her confirmation hearing last week, Evans told aldermen she planned to start the discussion by examining options along the Kennedy Expressway.

But on Wednesday, she raised an entirely new idea: running express trains to O’Hare on a second deck above the CTA’s Blue Line. She said knocking out Kennedy travel lanes to hold tracks did not make sense.

“What we really would need to do would be to add capacity. You can go over the top structurally . . . and use the dedicated right-of-way that’s already there,” she said.

The fact that the CTA is already spending billions to build a project it calls “Your New Blue” is not an impediment, she said.

“Engineering is always an iterative process. You can never exactly build things so that the next phase doesn’t require some re-work,’’ Evans said.

Experts said such “double-decker” service to an airport would be the first of its kind in the nation — and perhaps the world. Evans has said a higher fare could be charged for the premium service.

But Rick Harnish of the Midwest High Speed Rail Association warned that the second “deck” of track would probably have to rise over about 10 bridges that currently carry cars over the Kennedy between downtown and O’Hare.

Plus, Harnish said, existing Blue Line tunnels, near downtown and near O’Hare, do not hold enough space to run extra track for an express train.

Evans is hoping to have the “framework” completed in the next four years. That includes a “concept design” and “financial structure we know works,” along with operating agreements with federal, state and local agencies, she said.

She called the project a prime candidate for a federal Transportation Infrastructure Finance and Innovation Act loan reserved for projects of national significance that couldn’t be built otherwise.

“We need to be looking forward to being competitive 10 years from now, 20 years from now, 30 years from now and look at what services we need to attract those global business travelers and be on a par with other global gateway airports,” Evans said.

“If you look at Singapore and you look at [London’s] Heathrow and you look at Germany, having a premium rail service is definitely part of being part of an international premier gateway airport,” she said.

Evans also suggested the possibility of relocating concessions at O’Hare’s domestic terminals to a newly constructed, second-floor “mall” built in space currently occupied by offices.

That would allow space for a wider array of retail — including “higher-end” food and “activity offerings” like children’s play areas and game rooms — to occupy and entertain passengers and their children between flights.

In addition, it would create room for additional seating in gate areas that are so congested that passenger boarding queues stream into circulation areas, Evans said.

“The facility is kind of busting at the seams, particularly during peak periods,’’ Evans said. “Additional square footage means additional service. It’s as simple as that.’’

Evans acknowledged that building a second-floor retail mall might require structural and mechanical changes that could drive up the cost. It may also be “possible in some areas and not in others.” But, she argued, it’s “absolutely a viable concept” that must be explored.

“Fifteen years ago, that was considered a non-starter. Everyone [assumed] that passengers wouldn’t go up for concessions. That’s pretty much been debunked at Denver. They have a large number of mezzanine-level concessions that are extremely successful,” she said.

To reduce O’Hare delays, Evans talked about creating de-icing areas so planes do not monopolize gates during de-icing and adding more gates via “modules and pods” rather than a new terminal.

Evan’s expertise in delivering big-ticket projects is one of the biggest reasons Emanuel hired her to replace former Aviation Commissioner Rosemarie Andolino.

As vice president of engineering for the Metropolitan Washington Airports Authority, Evans was charged with overseeing Reagan National and Dulles International Airports, construction of the Silver Line Metrorail project and maintenance of the Dulles Toll Road.

She joined the Washington airport authority last year after serving as vice president for the global aviation practice at Parsons Corp., an engineering and construction giant.

Wearing a crisp black dress and sensible shoes, Evans looked like a no-nonsense, get-it-done-yesterday executive who will work well with a mayor who appears to be in a perpetual race against time.

As for the privatization of Midway Airport, Evans said she’s not about to go down that road again.

The idea has failed twice now: once for lack of financing under Mayor Richard M. Daley, the second time after Emanuel pulled the plug when only two bidders left the runway.

Although it might raise revenue, so would increasing the vitality of Midway, Evans said.

“I don’t see any reason to revisit [privatization of Midway]. . . . We’ve been down that path twice. It’s a very big distraction of time and resources,” she said and the idea “has proven to be a blind alley in the past.”

Noting that Midway is “at the bottom” among top 30 U.S. airports in both retail and food and beverage sales per passenger, she said, “There’s lots of ways the city can benefit from continued growth and improvements at Midway and we need to pursue all of those very vigorously.”

Evans said she also hopes to take the O’Hare Modernization Program over the finish line by convincing major airlines to bankroll an extension of an existing east-way parallel runway and to add another runway that airlines say they can’t afford and don’t need.

“We absolutely have to have a six-parallel runway system. There’s no question about that. There’s a lot of other components to OMP that we need to re-evaluate in terms of their sequence, in terms of their value, in terms of their cost estimate and in terms of exactly how we would achieve those goals. I’m very anxious to do that with the airlines and I have no doubt that we’ll have an outcome we can all agree on,” she said.

“There haven’t really been discussions in a very long time. . . . Two years is a long time in this business. Activity is up. Their profits are up. They have to grow. They’re in a different situation today than they were two years ago — a much different situation. There’s definitely an opportunity there.”