CHICAGO (CBS) — You don’t hear much about the ‘L’ station that sits abandoned, underground downtown, that was supposed to provide a terminal for express trains to and from O’Hare. But a prominent politician says she believes the idea still has promise.

Some call it one of the biggest boondoggles in Chicago history. Originally projected to cost $213 million, estimates for completion of The Block 37 CTA Superstation now run as high as $1.5 billion — money no one is racing to provide.

Construction began in 2005 and halted, well over costs and half finished, in 2011. No rails were ever laid in the station, said to be the size of a football field. CTA officials left it disconnected from the rest of the downtown subway system, unable to connect to either the Red or Blue Lines, which it sits between. But the concept still has at least one supporter — Cook County Board President Toni Preckwinkle, who voted for it as an alderman.

“I believed then it was a good idea, although it never came to fruition in the way Mayor Daley envisioned,” she told the spring meeting of the Midwest High Speed Rail Association. “I still think it’s a good idea, although how exactly we’re going to work it out I can’t tell you because I’m not that familiar with it.”

The city was supposed to pay $2.4 million of the costs, CTA $130 million and private partner Mills Corp., which at the time oversaw the Block 37 project, was supposed to pay $40.9 million. Debt incurred during the construction continues to cost the taxpayers $2 million a year.

Most recent discussion about a high-speed O’Hare link focuses on commuter rail lines.