Carl Sandell’s review published on Letterboxd :
The context alone makes this a captivating story, but it doesn't do much with this setup. Characters from all the major European nations stranded on a train that is pushing through China during a time of civil war. They are all spectators with no real interest in the conflict, but with a constant risk that they may get sucked in somehow. The confined space of the train is both safe as long as it is moving and vulnerable because it can't evade whatever obstacles come up, and it forces everybody together to interact and possibly deal with their own relations.
That political thriller part of the movie doesn't really develop into anything very interesting, but it works nicely as a backdrop of mystery and intrigue to the romance. Exciting use of light and shadows certainly helps the mysterious aspects and brings out the best of Marlene Dietrich. I'm not sold on her actual acting though. There's a detachment or even boredom that I guess is supposed to be mysterious and alluring. Perhaps it's the bland love interest that fails to create sparks for me, because I really don't care too much about their little affair. I would rather have had more Anna May Wong.