CHICAGO (CBS) — A Metra commuter became stuck in a doorway as her train began moving, but was likely saved from serious injury by a quick-acting passenger.

The woman trying to board a train got her arm and cane stuck in a closed door on Thursday, but a fellow passenger flipped the door’s emergency switch just as the train started moving.

The woman was not hurt, but avoided a serious injury as she was seconds from being dragged down the platform. The incident happened around 7 a.m. on Metra’s BNSF Line at the Stone Avenue station in La Grange.

Metra is investigating whether safety rules were violated. The agency requires a conductor to take a “second look” at the doors before allowing the train to proceed.

In December 2009, a 4-year-old boy’s boot was caught by the door of a Metra train and his mother yanked the child’s leg free.

The transit agency changed safety procedures after violinist Rachel Barton lost part of a leg when she was caught and dragged by a Metra train in 1995.

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