Anna is the 28-year-old former heiress to the Union Atlantic Railroad. Orphaned at 16 after a train explosion killed her brother and led to her parents' tragic deaths, she spends years meticulously planning a reckoning. Though she attempts to remain stoic and detached, her unresolved grief and lingering emotional connections make her quest for justice complicated.

Seamus is Anna's loyal accomplice in orchestrating the train journey. He forged a deep connection with Anna over their shared loss, having lost his own older brother in the 1942 train explosion. Tasked with maintaining order among the captive passengers, Seamus acts as the muscle and guard for Anna's plan.

Reggie introduces himself as an insurance salesman from Baltimore who accidentally ended up on the *Philadelphia Phoenix*. His sudden appearance destabilizes Anna's carefully controlled environment. He quickly proves to be observant, observing the tense situation while keeping his own motives and true identity closely guarded.

Dante is the charming, wealthy son of the rival railroad magnate Kenneth Wentworth. He boards the train by stealing his father's invitation. Having shared a brief, intense romantic relationship with Anna years ago before abruptly ending it, Dante brings an emotionally charged dynamic to the claustrophobic journey.

Kenneth is the ruthless owner of a rival railroad company who purchased Union Atlantic after its stock plummeted. He is the architect of the devastating plot to sabotage the 1942 military train, driven by a mixture of extreme greed and personal vengeance. Though initially absent from the train, his malicious influence looms over every passenger.

Jack is a 72-year-old retired lieutenant colonel who was instrumental in pushing the military contract that led to the fatal train explosion. Arrogant and uncompromising, he refuses to show remorse for his actions. He views the historical loss of life as an acceptable casualty for wartime readiness.

Sal is Arthur Matheson's former secretary. Once a warm presence in Anna's life, she radically changed her appearance and lifestyle after acquiring sudden wealth. She carries immense guilt for falsifying memos that framed Arthur, an act she committed to prevent Kenneth from exposing a deeply personal secret.

Edith is the Matheson family's former housekeeper. A German immigrant who helped raise Anna and Tommy, her maternal affection was ultimately overshadowed by her hidden sympathies and fear of blackmail. She hid crucial documents to frame Arthur, a choice that now haunts her with overwhelming regret.

Herb is a former factory foreman who oversaw the construction of the faulty locomotive. He squandered his illicit payoff on a lavish lifestyle and gambling, and he boards the train desperate for money. He is highly anxious and quick to panic when confined aboard the moving train.

Judd is the brilliant but bitter engineer who originally designed the *Philadelphia Phoenix*. Resentful of Arthur Matheson for taking credit for his designs, Judd willingly drafted the plans for the sabotaged military locomotive. He now works as a professor and boards the train knowing he must face the consequences of his actions.

Arthur was Anna's father and a highly successful railroad magnate. Falsely accused of orchestrating the 1942 military train explosion, his reputation was destroyed before he was brutally murdered in prison. His legacy and wrongful death serve as the primary catalyst for Anna's quest.

Margaret was Anna's mother, a woman of striking beauty who designed the interiors of the *Philadelphia Phoenix*. Devastated by the loss of her son and the subsequent destruction and murder of her husband, she drove her car into a river, leaving Anna completely orphaned.

Tommy was Anna's older brother who inherited their mother's striking looks. He enlisted in the military at 18 and tragically died when the sabotaged troop transport train exploded outside Raleigh, North Carolina. His death initiated the cascade of tragedies that destroyed the Matheson family.

Henrietta, or Aunt Retta, was Anna's wealthy, widowed aunt who took her in after her parents' deaths. Believing that emotions were a weakness, she employed harsh, physical methods to train Anna to be stoic. Before her death, she secured the evidence needed to prove Arthur's innocence and passed the mission of vengeance to Anna.

Sean was Seamus's older brother. He was one of the soldiers aboard the doomed 1942 troop transport train. His death in the resulting explosion continues to deeply affect his younger brother over a decade later.

Ed Vesper is an authority figure within the FBI. He intercepts the evidence Anna sent to Chicago and tasks Reggie with infiltrating the train to monitor the unfolding situation and ensure the evidence reaches its proper destination.