In terms of suspense and action, this is one of the weaker entries in the Shayne series. Most of the storyline is confined to a train ride carrying a secret witness to a west coast trial, who Shayne is supposed to protect from those who don't want her to appear. Unfortunately, not much use is made of the confined conditions to build suspense. Then too, we know early on the identity of the witness and who's on board to silence her, so there's not much mystery, either.
Fortunately, there is a sparkling cast, led by the breezy Nolan, along with a brassy Hughes and a bumptious Bari. In fact, Bari and Hughes are natural personality rivals, setting off some delicious undercurrents. Then there's an unheralded threesome of black porters, who contribute humorously to the overall lightweight mood. Look also for Louis Jean Heydt, a familiar face from that era, who does well with a larger than usual role. All in all, it's an entertaining 70-minutes, but not up to the series' trademark mix of suspense plus humor.