CHICAGO (CBS)– A woman died after falling onto Brown Line tracks early Friday morning.

The incident took place at the Rockwell station around 2:30 a.m.

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According to preliminary information from police, the woman was discovered on the tracks and investigators believe she was electrocuted when her leg touched the third rail.

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Police do not know how the woman got into the tracks, but said foul play is not suspected. She was not struck by a train. A death investigation is underway.

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Trains are running.