CHICAGO (CBS) — South Shore Line trains were more crowded than usual Wednesday morning, as crews continued working to restore normal service after a train derailed at Millennium Station on Tuesday.

Trains were running with fewer cars during the morning rush, after 18 cars were “trapped” at Millennium Station because of the derailment. Normal service was expected to resume Wednesday afternoon.

A westbound South Shore Line train derailed between Van Buren and Randolph around 2:15 p.m. Tuesday, leaving trains unable to enter or exit Millennium Station.

The train was moving slowly and remained upright. The Chicago Fire Department said one person was slightly injured after falling down.

While South Shore Line service was disrupted, Metra Electric trains honored South Shore tickets, but were delayed because the two lines share tracks.

South Shore Line trains began running on a regular schedule by Tuesday evening, but officials said passengers could expect more crowded trains through the Wednesday morning rush, because trains were running with fewer cars.

Everything was expected to be back to normal by Wednesday afternoon.