Everyone on This Train Is a Suspect by Benjamin Stevenson

From the bestselling author of Everyone in My Family Has Killed Someone, a fiendishly fun locked room (train) murder mystery that "offers a tip of the hat to the great Agatha Christie novel while at the same time being a modern reinvention of it" (Nita Prose) — perfect for fans of Richard Osman and Anthony Horowitz
When the Australian Mystery Writers' Society invited me to their crime-writing festival aboard the Ghan, the famous train between Darwin and Adelaide, I was hoping for some inspiration for my second book. Fiction, this time: I needed a break from real people killing each other. Obviously, that didn't pan out.
The program is a who's who of crime writing royalty:
the debut writer (me!)
the forensic science writer
the blockbuster writer
the legal thriller writer
the literary writer
the psychological suspense writer
But when one of us is murdered, the remaining authors quickly turn into five detectives. Together, we should know how to solve a crime.
Of course, we should also know how to commit one.
How can you find a killer when all the suspects know how to get away with murder?