by Adam Harrington, CBS Chicago web producer

CHICAGO (CBS) — Delays to the opening of the modernized People Mover at O’Hare International Airport follow a dispute between the city and the construction contractor responsible for the project.

The dispute between the Chicago Department of Aviation and the design-build contractor, Parsons Construction, resulted in a mediated settlement in August. The settlement established a new completion date for the People Mover, or Airport Transit System (ATS), of mid-November, according to a letter to the O’Hare Airport Community from Aviation Commissioner Jamie L. Rhee.

But a mid-November reopening is not in the cards.

“Both CDA and Parsons (and its subcontractors) have, in my estimation, been working in good faith toward delivering on that goal, but a mechanical issue discovered during on-track testing has made meeting it all but impossible,” Rhee wrote.

Rhee emphasized that it getting the new system online is a complex matter. Track construction is done, new railcars have bene delivered, and systems integration work is full speed ahead, Rhee wrote.

But the mechanical setback requires the whole system to be retrofitted – and because the new People Mover trains are driverless, propriety automated technologies that have not been used before must be tested properly.

“(T)he ATS will not return to service until we have absolute confidence in its safety and reliability. Period,” Rhee’s letter said. “At this time, there is no specific date for the ATS’s return to service, but we do expect it to be sometime in early 2020.”

Rhee wrote that the city does have some financial tools to “offset costs and hold the tractor accountable” as part of the settlement, but that issue is “for another time and another venue.”

The People Mover has been shut down since January.

A June Chicago Tribune report by writers Joe Mahr and Mary Wisniewski said the dispute between the Aviation Department and Parsons came as the People Mover project dragged out much longer than its initial expected completion date of December 2018. The newspaper said the contractor first asked the city to bring in shuttle buses for periodic shutdowns of the People Mover, and this year, it has not run at all.

The June Tribune report also said the city agreed to pay $23 million to Parsons if the work was done “largely completed by September.”

The Aviation Department was not immediately able to comment on the Tribune report, or about what has changed vis-à-vis its expectations from Parsons now that September is well in the past.

Parsons spokesman Bryce McDevitt said the company had no new statement about the O’Hare People Mover and referred questions on the project to the city.

As CBS 2’s Yasmeen Hassan reported Tuesday morning, the People Mover being out of service means people trying to get between terminals – or trying to pick up a rental car – need to leave the airport and get on a bus. For some, that is easier said than done – especially when you’re lugging around suitcases.