The Demon Train (#1 Rachel Payne Horror Series) - Rachel Payne Horror, #1

Rachel Payne is on her way to start a life new. Divorced, childless, and penniless, Rachel has nothing to show for her life, and nothing to lose. The life she has been living never felt right to her. She went to college, got a job, got married, had a house and cars, tried to have children but couldn't. While she tried to fit the mold of a "normal" woman in society, she always felt there was something else out there, waiting for her.
The 51 hour train route from Chicago to San Francisco proves to be the most dangerous trip she's ever taken. Plagued by nightmares and unable to eat or sleep, she begins to feel like she's losing her mind. Then, she and six other passengers become trapped in a train car by a sadistic, demon-possessed young man. Rachel is faced with betrayal and death as the demon exposes the passengers' deadly sins and threatens to murder them all.
Armed with only an innate ability to identify the demon for what it is, Rachel endures the first of many horrors that will inevitably consume her life.