Trains operating on the Chicago Transit Authority’s Red Line were experiencing “major delays” on Sunday afternoon as the result of a mechanical problem, the transit agency said.

In an alert at 2:50 p.m., the CTA said Red Line trains were running with “significant delays” in both directions following an earlier mechanical problem on a train at Sheridan. At around 4 p.m., crews were still in the process of working to restore service.

Specifics about the mechanical problem hadn’t been released.

Shuttle buses were transporting riders between Belmont and Howard in both directions. The CTA urged riders to consider alternate transportation methods in the meantime, including the following bus routes:

• #22 Clark
• #36 Broadway
• #151 Sheridan