Disappointing (some comments may be considered spoilers)

Rating: 5/10 (16 November 2017)

Beautiful sets, especially of train cars. But, other than the first two scenes, and first few minutes, of the film, in Jerusalem and Istanbul, all we see are four train cars: the Pullman Coach (sleeping compartments); the Dining Car; the luggage car (briefly); and the bar car. Almost all of the film takes place in the sleeping and dining cars. These are very narrow, confined spaces. So, the action is very limited. This isn't an action movie. But all that anyone can do is stand or lie down in a compartment in the sleeping car, stand or sit in the dining car. We're not talking about the absence of running, jumping, chasing, or whatever. We're talking about the near absence of body movement. Head turn. Vertical arm movement. Maybe a small hand gesture.
The acting was very good, of course. Top notch cast. The main cast (Detective Poirot, the Victim, and the Usual Suspects) includes Legends Judi Dench and Derek Jacobi, Stars Kenneth Branagh, Willem Dafoe, Michelle Pfeiffer, Johnny Depp, Penélope Cruz, Establisheds Josh Gad, Olivia Colman, Manuel Garcia-Rulfo, Marwan Kenzari, Lucy Boynton, and Leslie Odom, Jr., and Newcomers Sergei Polunin and Daisy Ridley.
I'm familiar with the works of the Legends and the Stars. I'm not at all familiar with the works of the Establisheds. I saw clips of Josh Gad in the abomination that is Disney's live-action Beauty and the Beast. Not particularly impressive, but that's no surprise given the vehicle. But I liked Gad's performance here. I liked everyone's performance. Never heard of Sergei Polunin. And, no particular reason, I don't expect to hear of him again. Among the Establisheds, it seems to me, Gad and Odom are the two most upwardly mobile.
Ridley's only other film work, of course, I know. Really no surprise that she, rather than some other similar age actress with more film credits (and I mean no one in particular), is here. Ridley held her own in good company. She, too, seems to be upwardly mobile.
Unfortunately, there wasn't much for any of the actors to do. I've never read the book and I've never (unless I've surpassed the memory of it) seen the 1974 film or any other adaptation. From what I understand, this is pretty much the standard version. Nothing unusual. Which makes me wonder why anyone cares at all. I found the story to be not at all interesting.
The film has two components: physical searching for clues; and interviews with the suspects.
Every interview goes like this
Poirot: "Who are you and why are you on this train?"
Person: "I'm person X, profession Y, going to Z for A reason."
Poirot: "No. You are person M, profession N. You are lying. And you are a suspect."
There are 13 of these. Maybe a quarter of the film.
(Possible Spoiler) I thought the solution was obvious before the halfway mark. I mean, after two or three interviews of suspects, it became, "WTF? Is anyone not ...?" And the answer is, "No. Everyone is ..." Which doesn't leave anything to the imagination.
I'm not a fan of mystery fiction. I haven't read any. I have no intention of reading any. I've seen some TV mysteries: Columbo (not whodunit, but howcatchim); Murder She Wrote (my mother loved this, of course); miscellaneous others over the years. It seems to me, a good mystery doesn't drop all the clues at the beginning, but drops them in what seems to be a natural sequence.
I don't know how this story was told in writing or previous adaptations, but it seems to me the writers of this film should have rearranged things quite a bit. There were no really dramatic moments. No ahas. The actors weren't part of a cohesive whole story. They didn't interact in any meaningful way. There weren't dialogues so much as a bunch of brief monologues or just statements.
(Compare, for example, with the scene in You've Got Mail where Meg Ryan, Jean Stapleton, Steve Zahn, and Heather Burns are standing at the cash register talking about the rooftop killer. I like these actors. But a scene from a silly little comedy shouldn't be, but is, better than any scene in MotOE 2017.)
And some of the things that people say and do, maybe they're supposed to be red herrings, but, in the end, they just don't fit. For example, papers being destroyed to prevent discovery of a crime that the criminal had no reason to commit; and one person taking blame for what another person has been accused of doing, even though the blame-taker knows the other person didn't do what the person has been accused of doing, and neither of these people handle the situation in a (dramatically) reasonable way. Worst of all, when these things are happening, we already know they aren't correct or relevant.
(Possible Spoiler) The only dramatic moments are those that appear in one of the trailers; about 60 seconds of a two hour film.
And who the hell is Katherine? or Catherine?