Brad Pitt makes a riotous return to action comedy on board “Bullet Train,” a Japanese hitman-among-hitmen thriller of the “Mass Murder on the Orient Express” variety.

Stuntman (“John Wick”) turned “Deadpool 2/Hobbes and Show” director David Leitch puts Pitt through his punchout paces in a laugh-out-loud melee that’s “Seven Psychopaths,” “Pulp Fiction/Hateful Eight” and “Free Fire” — pretty much any movie about murderers murdering murderers — rolled into one.

It’s got set-piece brawls and star cameos, a “MacGuffin” and old grudges and characters named The Wolf, The Hornet, White Death and The Elder, with one nicknamed “Ladybug,” for “luck.”

Based on a novel by Kôtarô Isaka, it’s pure popcorn, a wildly illogical, nonsensical zip through cultures clashing and knives slashing with assorted killers running afoul of each other — but not “civilians” among the passengers, rarely the crew and never the police.

Pitt plays a “snatch and grab” specialist hired to swipe this briefcase on a long, fast train ride. Simple, right? The Nippon Speedline makes stops, but they’re precisely timed at one minute each. “Snatch” the case, pop off at the next available stop and nobody’s the wiser.

His com-linked “handler” has codenamed him “Ladybug,” and is puzzled why he’s passed on taking along the pistol she left for him, because “some conflicts require a gun.”

Not our “Ladybug,” who is in therapy and “experiencing a calm like never, ever before…You put peace into the world, you get peace back.”

Sure.

But grabbing that briefcase puts “The (British) Twins” (Brian Tyree Henry and Aaron-Taylor Johnson) on his trail. “Not really sure they’re ‘twins.'”

He runs into a Mexican murderer (Bad Bunny), who instantly pulls a knife and tries to end him.

There’s “The Prince” (Joey King), who may look and sound like a British school girl, but isn’t. She’s lured a father (Andrew Koji) whose little boy she shoved off a hotel roof. But she doesn’t know the father’s knife-scarred old man (Hiroyuki Sanada) is shadowing them.

And behind the scenes, some Russian born Japanese crime lord named White Death is calling for growled updates and pulling strings to get his son (Logan Lerman) off that train, and the ransom money he’s paid for him returned in full.

Our Ladybug is trapped in a “John Wick” world where everybody’s a killer, many of whom he’s crossed paths with (“Johannesburg,” “Bolivia,” “Mexico”), in constant touch with his handler/confessor (“Grosse Pointe Blank”) and forever sharing what his therapist “Barry” has taught him about a new way to look at the world.

“Let this be a lesson on the toxicity of anger!”

Leitch and screenwriter Zak Olkewicz (“Fear Street: Part Two” on Netflix) play around with the clash of cultures. One car on this train in “Hello Kitty” obsessed Japan has kitty themed seats and even a plush mascot.

One killer learned how to judge character and face the world via “Thomas the Tank Engine.” No, you don’t want to be the “Diesel” on board this fast train. Not in his eyes.

It’s all knives and samurai swords and booby-trapped pistols and never-for-one-minute logical. A team of minions get on the roof at one stop. Why? To be killed off, of course.

Everybody takes a beating/cutting/shooting, with character after character settling onto the train with barely-discrete blood stains on their fine threads, many hurled off it or out of it later en route or at the next scheduled stop, all of them hellbent on getting back on and finishing what they started.

Pitt’s Ladybug? He’s as innocuous as an “I could live here” tourist. In thick glasses and a floppy hat, he could pass for Woody Allen with a Johnny Depp aversion to ever getting a haircut again.

The cameos and third act actor introductions turn this into an all-star romp — of sorts — further lightening the tone.

Like “Wick” and “Deadpool,” it all gets to be a bit much. The pace and energy eases up for assorted flashbacks. The best gags are running gags, the funniest lines the ones repeated — about a Black Briton and White Briton who are nobody’s idea of “twins,” about where Ladybug’s head space is, about everything “Thomas the Tank Engine” has to teach us about life.

In a summer where all the action has had its lighter touches, “Bullet Train” rolls in just in time for Pitt and Pals (in some cases, literally) to bookend the cinema season with a fine and furious companion piece to “The Lost City,” which opened festivities and invited audiences back into theaters in April.

It’s a new-fangled, old-fashioned E-ticket ride of a movie and an amusing exclamation point to put on the year that brought filmgoers back to theaters for the magic — and mayhem — of the movies.

Rating: R for strong and bloody violence, pervasive language, and brief sexuality.

Cast: Brad Pitt, Joey King, Brian Tyree Henry, Hiroyuki Sanada, Aaron Taylor-Johnson, Bad Bunny, Zazie Beetz and Sandra Bullock.

Credits: Directed by David Leitch, scripted by Zak Olkewicz, based on a novel by Kôtarô Isaka. A Sony/Columbia release.

Running time: 2:06