CHICAGO (CBS) — Trains on the CTA’s Brown and Purple lines were running on normal schedules and rolling over the Wells Street Bridge again, after the second half of a project to replace the bridge was completed early Monday.

WBBM Newsradio’s Bernie Tafoya reports, in two nine-day stretches, iron workers and electricians were able to remove the 90-year-old, 500-ton double decker bridge over the Chicago River, and replace it with a brand new one.

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The southern half of the bridge was replaced in early March, and the northern half was replaced last week.

“We want to thank our customers for their patience. We know that they experienced on these two different line cuts overcrowded conditions and an inconvenient commute, but I think it’ll be worth it,” CTA President Forrest Claypool said.

CTA spokesman Brian Steele said, over the past nine days, there were only 20 online complaints from inconvenienced riders.

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Mayor Rahm Emanuel said the way the CTA coordinated work with the Chicago Department of Transportation ended up saving taxpayers $500,000.

“We just saw the train … with commuters today go to work, on a bridge that … again goes down for Chicago as an engineering feat,” he said.

Despite the inconvenience for Brown and Purple line riders, who had to use shuttle buses or Red Line trains to get where they were going while the bridge was closed, Emanuel said it was worth it. The project was timed so eight of the 18 total days of work took place on weekends, when the Brown Line is less crowded, and the Purple Line does not run downtown.

Approximately 77,000 people a day use the Brown and Purple line trains that cross the Wells Street Bridge.

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Work continues on the street level of the Wells Street bridge, so it will remain closed to cars, buses and other vehicles until November.