A suspect has been taken into police custody and the victim has been taken to a nearby hospital, according to BART.
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A witness said he was on his way home on the train when the stabbing victim came up to him, asking for help.
"There was a lot of blood coming out of this guy," is how BART passenger Anthony Montemar described the victim, who he says is an Asian man, possibly in his 50s.
"He was bloody, two neck stab wounds, abdomen stab wound. He was bleeding all over. He was a little incoherent, but he pointed at that car that he came out of," said Montemar.
When Montemar looked towards the car that the victim pointed at, he said could see a man running in the opposite direction.
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Montemar said he helped get the victim to the driver's car, where they called police to the Warm Springs BART Station.
Montemar doesn't think the two men knew each other.
"From my understanding, from what it looked like, the (suspect) kind of flipped out and just stabbed the (victim). I don't know what the altercation was. They looked completely separate," Montemar said.
It's unclear how severe the victim's injuries are or what led up to the stabbing.
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The Fremont BART station has since reopened and trains are running normally.
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