Two people were killed and one person was seriously injured in three separate train incidents, all occurring within just seven hours.

The first incident occurred at around 10:50 p.m., at the Brighton Beach B station, according to police. The victim, an unidentified man, was struck by a B train—he was trapped under the train briefly and lost his arm, but he is expected to survive.

At 11:20 p.m., police say a man was fatally struck by a train at the B/D station on 155th St. and Frederick Douglass Blvd. Cops say he was walking across the tracks separating the uptown and downtown platforms when a downtown D train hit him. He was pronounced dead at the scene.

And at around 4:50 a.m., in the Bronx, an unidentified man jumped in front of a southbound 1 train at the 231st St. station, according to police. He was also pronounced dead at the scene.

If someone you know exhibits warning signs of suicide: do not leave the person alone; remove any firearms, alcohol, drugs or sharp objects that could be used in a suicide attempt; and call the U.S. National Suicide Prevention Lifeline at 800-273-TALK (8255) or take the person to an emergency room or seek help from a medical or mental health professional.