In the new “Murder on the Orient Express,” Agatha Christie’s beloved Hercule Poirot (Kenneth Branagh) can be seen thoroughly enjoying a Charles Dickens novel before he’s interrupted with the nasty business of a murder.

It’s appropriate. Branagh is as classical as any director working today, able to dip into literary treasures ranging from Shakespeare and Mary Shelley to Cinderella and Thor, and bringing freshness and energy to all.

He’s also one of the best actor-directors working today, and his wearing of two hats on “Murder on the Orient Express” recalls his exuberant work on “Henry V” (1989) and “Hamlet” (1996), as well as on the nifty little crime film that was his sophomore effort, “Dead Again” (1991).

The only other big-screen “Murder on the Orient Express” — directed by Sidney Lumet in 1974 — featured Albert Finney as a finicky Poirot. Branagh, with his world-class mustache, easily equals him here.

This Poirot is painfully aware of his shortcomings, of how ill-fit he is to mingle with others. When alone, he sometimes tragically consults a photo of a lost love.

He’s exhausted, and after solving a crime in Jerusalem (involving a priest, a rabbi and an imam), he wants nothing more than a vacation.

Unfortunately, he is called back to London and must board the Orient Express. There, he meets a sinister, scar-faced “businessman,” Ratchett (Johnny Depp), who claims he is in danger and asks for Poirot’s protection. Poirot declines.

Next thing, Ratchett is dead, murdered, and the train is full of suspects: Ratchett’s secretary (Josh Gad), his valet (Derek Jacobi), a society lady (Michelle Pfeiffer), a princess (Judi Dench), a professor (Willem Dafoe), a governess (Daisy Ridley), a doctor (Leslie Odom Jr.), and a missionary (Penelope Cruz) among them.

Like Lumet, Branagh, attempting to get behind human aspects of this crime, is not overly focused on suspense or thrills.

The skillful camerawork does not use cramped, limited setting to build claustrophobia or paranoia. Rather, his camera glides alongside the train and peers through windows, or floats overhead, giving actors room to move in the corridors.

The movie even finds wide, establishing shots to assemble the suspects into a single, inseparable group. The striking denouncement scene takes place at the mouth of a train tunnel lit by flaming torches.

Mostly, the bright, fluid, elegant “Murder on the Orient Express” seems refreshingly smart and old-fashioned, like an export from the old studio days of Hollywood.

Even the screenwriter, Michael Green, has proven adept at brushing off and freshening up old characters, as he did in this year’s “Logan” and “Blade Runner 2049.”

While those with short attention spans may find “Murder on the Orient Express” irrelevant, for the rest of us, it’s a fine, diverting entertainment in all the best ways.