The Roosevelt Tunnel built under the Waldorf Astoria to which Ryder uses as part of his escape from the subway is actually based on the secret track 61 which is built under the Waldorf Astoria and was commissioned to help President Franklin Roosevelt keep his use of a wheelchair secret.
The R-142 and R-142A subway cars portrayed in this film are permanently linked into 5-car sets and cannot operate as single units. R-62A 2079, a single car capable of operating alone, was cosmetically modified to resemble a modern car for this film and restored to its original appearance after filming was completed.
The movie pays homage to Walter Matthau, who played Lt. Zachary Garber in the 1974 movie by naming 'Denzel Washington's character Walter Garber. Also, while Lt. Zachary Garber wore a plaid shirt and yellow tie, Walter Garber wears a yellow shirt and similar pattern plaid tie.
Garber talks about choosing between purchasing trains from a Japanese company and a Canadian company. Although not mentioned by name, this refers to Kawasaki Heavy Industries and Bombardier Transportation, who have both manufactured subway trains for New York.
Ryder says to Garber, "You live, you die, you either go with the current or you fight it, but you all end up in the same place", to which Garber asks, "Where's that, Jersey". Ryder then says, "Yeah, you watch it, I was born there man." John Travolta, who plays Ryder, was born in Englewood, New Jersey.
The title derives from the train's radio call sign. When a New York City subway train leaves to make a run, it's given a call sign based on the time it left and where, in this case Pelham Bay Park Station at 1:23pm.
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 Although the policy was rescinded, as a superstition the dispatchers still avoid scheduling a train at that time.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 ending in the novel is different to this film and the original; in the original film, the last remaining robber says something incriminating to Walter Matthau, and in the remake, Garber kills Ryder and the cops kill the last two remaining robbers.
While negotiating with Garber on the phone, Ryder says the hostages aren't getting pizza. In the movie Inside Man, Denzels Washington's character is a hostage negotiator who sends in pizza for the hostages being held in the bank.
In the movie, from the audience's viewpoint, Ryder (John Travolta) is seen wearing an earring on his right ear while Walter Garber (Denzel Washington) has one on his left. Also notice that both of them has only a single earring.
In the novel, the Mayor has flu but in the remake he says he always gets flu when visiting schools so wants a flu shot on standby. But the Mayor is ill with something that could be life-threatening. His wife is in the novel but they've separated in the remake because of his infidelity.
In the novel, Ryder's mother died of cancer and his father was bludgeoned by an ashtray. He entered military service like Vietnam and perhaps this was the case in the original film but doubtful the remake.
In the novel, the first time we meet the Mayor is at his mansion, having a tryst with a monk, and not on another train like the remake. In the remake, his marriage is in trouble but not for the same reason. The Mayor (Sam in the novel) even considers letting the hijackers keep the train because New York doesn't have a million dollars, which was a lot of money in 1973 when the book was written.
In the film, Ryder wants Garber to deliver the money, but in the novel he wants cops to drop it off in ten minutes or he kills a hostage. There is no road accident that makes them miss the deadline or lying to Ryder that they've got the money.
In the novel, the hostages tell Ryder why they need to be released and he says why they can't, but not the remake. An off-duty cop is on the train too but not the remake, where he takes matters into his own hands at the climax. He shoots Ryder in the tunnel, but Ryder dies by electrocution in the original film, but is killed by Garber outside in the remake.
The equivalent of Garber in the novel is someone called Prescott and he's not as level-headed as Garber in the remake. He's an operations lieutenant and a minor character and views the escape from the train at transit police headquarters.