CHICAGO (CBS) — Service on the South Shore was mostly restored Tuesday evening, hours after a train derailed as it was arriving downtown before rush hour.

A westbound train No. 18, which originated in Dune Park, derailed between Van Buren street and the final stop at Millennium station at Randolph street around 2:40 p.m.

“South Shore trains are unable to enter or exit the station,” South Shore said on its website. “Passengers are encouraged to find alternative transportation for their eastbound trip. Metra is honoring South Shore tickets.”

A South Shore trail derailed on Tuesday. (Credit: Danny Crook)

The train appeared to derail in an area where trains switch tracks as they enter the corrals at Randolph street. The train was moving slowly when it derailed.

South Shore train deraled downtown on Tuesday. (Credit: Danny Crook)

Metra Electric trains were also delayed because the two lines share the tracks, but officials expect to have normal rush hour service.

Chicago Fire Department said one person was slightly injured after falling down.

Later Tuesday, South Shore operators announced regular service had resumed, but noted it would operate with fewer cars on Wednesday. Nearly 20 cars were “trapped” at Millennium Station because of the derailment.

Crowded conditions were expected.