i watch this one mostly to see charlie ruggles and una merkel and two of my favorite . the plot have many a twist and turn it not bad a a straight mystery aboard a train . but why throw in a circus train wreck and an escaped gorilla . i can mention this without it be a spoiler because the circus train wreck and the gorilla have nothing to do with the intricate mystery plot . the bad person try to kill the good people have many trick up his sleeve and but the circus train wreck be purely coincidental . it allow for a single scene with a menacing gorilla and but then it back to the murder mystery .