CHICAGO (CBS) –It’s a big hassle for thousands of CTA riders and it’s all to replace a major Chicago bridge.

Riders will have to navigate their way to the loop without the Brown or Purple lines for the next week. The lines are out of commission so a new span of the Wells Street Bridge, can be put into place.

Both lines use the bridge to move North-Siders and folks coming from Evanston, across the Chicago River, into the Loop.

Late Friday night, the nine-day shutdown began. CBS 2 was there as the last CTA trains made their way over the river. The old south span being replaced, followed by a new roadway, sidewalks, and train tracks.

Details Of Brown Line Changes

(Some Brown Line trains run from Kimball and stop at the Merchandise Mart. During rush hour, others will switch to Red Line tracks at Fullerton and make stops until Roosevelt. Note the brown hash lines along Red Line route. The destination signs on these trains will read “Roosevelt” on a red background. Overnight (after 10 p.m.), trains will stop at Chicago Avenue.)

If you ride the Purple Line, you will now have to transfer to the Red Line at Howard Street. Brown Line riders will get off at Chicago, where free shuttles will take commuters into the Loop.

Some trains will continue south, following Red Line stops through Roosevelt.

Riders are being advised to leave early, and prepare for a longer commute.

“Our concern is that many people might not be as prepared as we would like them to be,” said Brian Steele of the CTA.

The Wells Street Bridge is expected to be re-open in time for rush-hour Monday, March 11.

The Wells Street Bridge will be close a second time for another nine days beginning at the end of April, to replace the bridge’s north span.

Free Shuttle Bus Route

No. 37 Sedgwick Bus Map

No. 37A Sedgwick Bus Map RUSH HOUR