If Hercule Poirot were alive in the 2010s, we’d say he has OCD for sure, what with his fixation on measuring his soft-boiled breakfast eggs to make sure they’re the same size and his frustration with anyone whose tie isn’t straight.

We’d also say Poirot has no social filter. As the great detective goes about his day, observing everything and missing nothing, he won’t hesitate to tell someone to stop talking “because you’re just making it worse,” or telling a new acquaintance, “I’m just as disappointed with you.”

He also laughs uproariously while reading “A Tale of Two Cities,” as if Dickens had written the funniest comic novel ever.

Nobody in “Murder on the Orient Express” seems the least bit put off by or even slightly disturbed by Poirot’s peculiarities. Quite the contrary. This being the early 1930s and Poirot being the most famous and accomplished detective in the world, almost all seem delighted and captivated and mesmerized by Poirot’s zany, meticulously kept mustache and his direct manner of speaking — even when he’s catching them in a lie.

“You’re a very clever man!” says a glamorous murder suspect when she’s caught in a web of deceit. She nearly breaks into applause.

Kenneth Branagh is the director and the star of this new adaptation of Agatha Christie’s time-honored classic “Murder on the Orient Express,” and never let it be said the director misses an opportunity to place his star front and center, unfortunately relegating just about everyone else in the obligatory International All-Star Cast to a paper-thin character with one or at most two defining personality traits.

(They also get one to two scenes apiece to join Branagh in the center of the stage — I mean, in the forefront of the film — to flex their acting muscles and to act surprised or delighted or flummoxed by the great Poirot’s powers of calculation.)

Branagh is a world-class actor and a fine director, and he scores stylistic points on both counts here, but this “Orient Express” loses steam just when it should be gaining speed and racing to its putatively shocking conclusion, which isn’t all that surprising — even if you haven’t read the book or seen the 1974 movie starring Albert Finney and directed by Sidney Lumet. (For those who HAVE consumed one or the other, I shan’t reveal if this edition stays true to the source material to the very end.)

Keen to take a long holiday after solving yet another crime in spectacular fashion, Poirot boards the Orient Express heading from the Middle East to Europe, and is soon engaged with a number of mysterious and perhaps shady characters, including one Edward Ratchett (Johnny Depp, looking pale and uninterested), a corrupt, gun-toting art dealer on the lam from some wronged parties who want him dead dead and dead.

Ratchett tries to hire Poirot to watch his back. Poirot says no. He doesn’t protect criminals; he solves crimes. Besides, he tells, Ratched: “I don’t like your face.”

Not long after, Ratchett is found dead in his cabin. An avalanche has conveniently derailed the Orient Express, leaving everyone trapped on the train and looking over their shoulders as Poirot searches for clues and motive and interviews them one by one.

What a bunch. Michelle Pfeiffer (who gives the best performance in the film) is Caroline, a beautiful woman of a certain age on the hunt for her next husband. Penelope Cruz is Pilar, a deeply religious nurse. Josh Gad is Hector, accountant and assistant to Ratchett. Leslie Odom Jr. is Dr. Arbuthnot, impatient to get to London.

Daisy Ridley is Miss Marry Debenham, a governess who seems to have a strong connection to Dr. Arbuthnot. Willem Dafoe is the Austrian scientist Gerhard Hardman, who has some chilling views on race and social status. (We meet a half-dozen others along the way as well.)

At least those are the names and profiles first presented to Poirot. It’s not long before he begins peeling away the surface lies and discovering multiple connections to a long-ago, tragic and very famous case involving the kidnapping and murder of a child in America.

Branagh the director creates some marvelous visuals, including long tracking visuals where we are outside of the train, peering through the windows at the various characters, and the meticulously appointed dining and sleeping cars on the magnificent train.

Branagh the actor cracks off a half-dozen amusing one-liners. The veteran performers are just fine, of course, but the great Judi Dench and the legendary Derek Jacobi are virtually lost in the clutter of characters. (Of the younger set, Ridley and Gad deliver the best work.)

When finally the Orient Express chugs to a halt and we learn how and why and when the murder was committed, the prevailing thought is:

My dear. It could have been done in a dozen or more so much simpler ways.

★★1⁄2

20th Century Fox presents a film directed by Kenneth Branagh and written by Michael Green, based on the novel by Agatha Christie. Rated PG-13 (for violence and thematic elements). Running time: 115 minutes. Opens Friday at local theaters.