The glamorous passenger train Twentieth Century Limited, which ran between New York and Chicago between 1902 and 1967, is the main setting of this musical screwball comedy’s action. Oscar Jaffe, an egomaniacal Broadway producer who has sustained a string of recent flops and is now dodging creditors, boards the train heading to New York. On the train, he spots his former Broadway leading lady and muse, Lily Garland, now a Hollywood movie star, and schemes to have her signed to star in his new play and thereby save his career and stay out of jail. But she’s on her way to meet with his competitor, Max Jacobs, to sign up for his play. Jaffe believes he’s found an investor in a fellow passenger and heiress, the religiously fervent Letitia Primrose, who could write a check big enough to entice Lily to renew her working relationship with Oscar and save his show. But Ms. Primrose is certifiably insane. There’s action, a little romance, fast-paced dialogue and a dash of slapstick.