John Travolta chose not to promote the film with the rest of the cast because he was still reeling from the loss of his son Jett.
The New York Transit Authority for years after the novel and the original film barred its planners from scheduling a train leaving Pelham at 1:23 in the morning or afternoon. Although the policy was rescinded, as a superstition the dispatchers still avoid scheduling a train at that time.
The movie pays homage to Walter Matthau, who played Lieutenant Zachary Garber in the 1974 movie by naming 'Denzel Washington's character Walter Garber. Also, while Lieutenant Zachary Garber wore a plaid shirt and yellow tie, Walter Garber wears a yellow shirt and similar pattern plaid tie.
The production team worked closely with the MTA and was given access to the MTA control room for research.
One of the bad guys was a Teamster on the set with an actual criminal past who Tony Scott hired because he felt he played a bad guy convincingly enough.