Raymond Demetreius Bonner, 36, allegedly stabbed the victim in the neck as he was walking onto the platform Sunday morning.
MORE: Man stabbed in neck by suspect at Riverside Metrolink station
Surveillance video and a tip led to Bonner's arrest in Moreno Valley on Monday.
Bonner is being held on $1 million bail.
As for the victim, he remains in critical but stable condition.