CHICAGO (CBS) — Two cars were blocking Metra Electric District tracks on the South Side, after a crash Friday morning.

POlice said two cars crashed at 71st and Stony Island shortly after 6 a.m.

Both vehicles ended up blocking the Metra Electric tracks that run between the eastbound and westbound lanes of 71st Street.

Metra said two Electric District trains were stopped as a result of the crash.

Police said a 48-year-old man was taken to the University of Chicago Medical Center in serious condition. A 52-year-old woman also was taken to the University of Chicago with minor injuries.

The cause of the crash was under investigation.