All aboard for the most famous crime ever to be committed and solved on a train — “Murder on the Orient Express,” headlining a trio of Agatha Christie’s Poirot mysteries starring David Suchet. The long-awaited adaptation is preceded by DAVID SUCHET ON THE ORIENT EXPRESS: A MASTERPIECE SPECIAL , a one-hour special aboard the present-day iconic train. In “Third Girl,” Poirot teams with Ariadne Oliver (Zoë Wanamaker), a crime novelist said to be modeled on Christie herself. And in “Appointment with Death,” the Belgian sleuth focuses his detective genius on an archaeological site in Syria, where a fabulous ancient artifact has come to light — in addition to a modern corpse.