CHICAGO (CBS) — Mayor Rahm Emanuel has vowed to resurrect a plan to provide express trains between O’Hare International Airport and downtown Chicago, a project long touted but ultimately abandoned by his predecessor, Richard M. Daley.

The mayor called the project “essential to the future of the city of Chicago.”

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“If London and Hong Kong and Tokyo and Toronto can offer this service, the city of Chicago can and must also offer it. We have been hearing from potential investors and companies from around the world about their interest in this project,” he said.

Emanuel has set a three-year-goal to get started. He said he already knows of investors interested in the project, but has not offered details on how much it would cost, or how it would be financed.

Former Mayor Daley frequently discussed the idea of creating high-speed train service between the Loop and O’Hare, and had planned to use the Block 37 shopping mall as the home for a downtown terminal.

Construction began in 2005 and halted in 2011, after running well over budget, despite being only half-finished. No tracks 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.

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City officials have since said the Block 37 superstation would not be considered for the downtown terminal for O’Hare express trains.

The Emanuel administration has hired an engineering and design company to come up with the vital details of the plan – including potential routes, the location of the stations at the airport and downtown, and a cost estimate for the project.

Fares would likely cost $25 to $40 for express trains that would get travelers between O’Hare and the Lop in 20 to 25 minutes – approximately half the time of the average Blue Line ride.

The exact route of the express trains has yet to be determined. One possibility that has been mentioned is building a second deck above the Blue Line along the Kennedy Expressway.

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Meantime, the city was set to break ground Friday on a new $18 million airport maintenance facility at O’Hare. The 90,000-square-foot annex to the existing Airport Maintenance Complex on the south airfield sill house O’Hare’s entire fleet of snow removal equipment. The annex should be completed by next winter.