Updated 01/26/15 – 1:20 p.m.

CHICAGO (CBS) — Service on the ‘L’ tracks in the Loop was back to normal Monday afternoon, after a major headache during the morning commute forced the CTA to reroute three train lines, and riders were delayed as long as 90 minutes.

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The CTA said the cause of the problem was a switching issue near the spot near Wabash and Van Buren, where Orange and Green Line trains enter the south end of the Loop. The heavy morning traffic on the ‘L’ slowed repairs, and created major delays on all five train lines that use the Loop tracks — the Brown, Green, Orange, Pink and Purple lines.

Brown Line trains were rerouted from the outer Loop tracks to the inner tracks; Orange Line trains were rerouted from the inner tracks to the outer tracks due to congestion, and Purple Line Express trains were rerouted to the Red Line subway due to congestion.

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Service was slowly getting back to normal by late Monday morning. Most of the congestion had been cleared, and Orange Line trains were back running on the inner Loop track by 9:30 a.m. Brown Line trains resumed normal service on the outer track around 1:15 p.m.

On Twitter, several riders complained that they were delayed as long as 90 minutes due to the mess on the Loop.

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