I watched this one mostly to see Charlie Ruggles and Una Merkel, two of my favorites.<br /><br />The plot has many a twist and turn -- it's not bad as a straight mystery aboard a train.<br /><br />But why throw in a circus train wreck and an escaped gorilla? I can mention this without it being a "spoiler" because the circus train wreck and the gorilla have nothing to do with the intricate mystery plot.<br /><br />The bad person trying to kill the good people has many tricks up his sleeve, but the circus train wreck was purely coincidental. It allows for a single scene with a menacing gorilla, but then it's back to the murder mystery!