CHICAGO (CBS) — For the second time in two months, the Wells Street bridge over the Chicago River has been closed (as of 10 p.m. Friday) to CTA ‘L’ trains, and the Brown Line has been cut off from the Loop until May 6.

CTA is urging riders to leave early and expect delays, and a majority of riders interviewed by WBBM Newsradio at the Sedgwick stop in Old Town Friday seemed content with that advice.

Once again, riders will be linked to affected stations by a bus shuttle. Some ‘L’ trains will venture as far south as Chicago Avenue or the Merchandise Mart during rush hours, but the majority will be routed through the Red Line subway to Roosevelt Road, where they will be turned for the return trip to Kimball.

Until the spans are swapped out, anticipated by CTA and the Chicago Dept. of Transportation (CDOT) to be May 6, Purple Line express trains will operate. All Purple Line rush-hour trains will run local stops between Linden and Howard, then return to Linden.

As a result, extreme crowding is possible on the Brown and Red Lines entering the Loop in the morning and leaving in the afternoon.

Green Line trains also will be affect this weekend and next, as comprehensive work is completed on CTA’s Tower 18, which guards the rails above the corner of Lake and Wells. The tower is the busiest on the CTA system and for decades has been one of the busiest rail junctions in the world.

This weekend and next weekend, Brown Line trains will run only as far as Chicago/Franklin; Pink Line and Green Line trains originating at Harlem will run only as far as Clinton; Green Line trains operating from Ashland/63rd and Cottage Grove will run only as far as Adams/Wabash (commuters can transfer to a shuttle train that runs to Clark/Lake); and Orange Line trains from Midway will run only as far as Washington/Wells. A substitute bus service between the Clinton and Chicago stations and connecting to the Loop “L” will operate during the weekend.

During the weekday morning rush, two out of every three southbound Brown Line trains will be routed via the Red Line subway to Roosevelt. Confusion during the first round of bridge replacement prompted CTA to make one change. Spokesman Brian Steele said that all trains that will enter the subway south of Fullerton — two out of three trains — will stop at the inner side of the Fullerton platform on what is normally the Red Line track.

Brown Line trains that don’t enter the subway — one out of every three southbound Brown Line trains — will terminate at the Merchandise Mart. Steele said that Brown Line trains remaining on the ‘L’ structure will stop, as always, on the outer side of the platform.

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