This is quite a clever little mystery, well held together by Edmund Lowe and Constance Cummings. The former is a cocky PI ("Harwood") who meets ("Miss Fenton") who works for an insurance company. They must get to the bottom of some rather ingenious murders. Each time, an heavily insured body is found in a train wreck. One might be plausible, but after a few of these the coincidence theory starts to wear thin, and a clever strategy emerges which they must thwart. Initially, of course, the pair are pretty hostile towards each other and as we progress their acerbic rapport becomes witty and entertaining. The pace is good, the supporting cast which includes Felix Aylmer and Thomy Bourdelle delivers well too, and by the end there is still plenty of jeopardy as to whom is pulling the strings (or the emergency cord!). The action scenes are quite authentic looking too and there is definite sense of entertaining peril for us to enjoy.