NAPERVILLE, Ill. -- Authorities say an Amtrak train conductor was shot at a train station in the Chicago suburb of Naperville.

Naperville police say a Wisconsin man in his 70s fired from inside the train after the conductor stepped onto a platform from the Southwest Chief headed to Chicago from Los Angeles. The unidentified conductor was struck in the stomach.

Naperville Deputy Fire Chief Andrew Dina says the victim was taken to a hospital. No information was given on the man's condition, but police say he was conscious and alert.

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In a statement, Amtrak said the conductor sustained a non-life-threatening wound.

Police Cmdr. Louis Cammiso says passengers held the alleged shooter until police arrived and took him into custody.

"I just know the conductor stepped off the train on the platform, and the suspect was on the train and reached through a window and shot the victim," Cammiso said. "Some passengers assisted the victim, and some passengers secured the suspect and held him for police."

A handgun was recovered at the station, CBS Chicago reports.

Authorities said they haven't determined a motive for the shooting, adding a handgun was recovered at the scene.

The shooting occurred during the Tuesday evening rush hour, temporarily halting Metra commuter rail service into and out of Chicago.