The Paris-Istanbul Orient Express train service ran from 1883 until 2007. There are some cheaper incarnations on the rail still, mostly in Italy, but they’re not the storied original. What could be?

That changes this year, when Accor aims to relaunch an Orient Express using 17 restored 100-year-old cars.

Given the luxuriousness, it’s understood that it takes more than a conductor, engineer and a brakeman to run the train. There are multiple attendants, porters and a kitchen staff too. Essentially, an ensemble.

An ensemble is what you have at Theatre Aquarius next month with the presentation of “Murder on the Orient Express,” a 10-person play based on the Agatha Christie murder-mystery.

“I hate having to do it all myself,” Daniel Kash joked during a recent interview.

Kash plays Hercule Poirot, the ever-watchful, ever-detecting, seriously mustachioed Belgian hero of many Christie novels. But Kash pivoted to serious quickly, admitting that he’s “never believed in the concept of the leading actor,” having trained in an English theatre that took what he called a socialist approach to cast and crew.

“Everyone (in the Playbill), from the actors to the person working in the laundry, was listed. In alphabetical order. We offered free shows for people on the dole,” Kash said. “And the audience is into it too. As an actor, it’s like, ‘you’re here with me.’ You feel the tickle of where they’re at. We’re all telling the story together.” (The Aquarius cast and crew are listed alphabetically as well).

For Kiana Woo, being part of an ensemble is “about building a relationship, building a language. It’s nice to be in a room with others, all having to work together to build this world.”

“Specifically, who did what, trying to figure out the character. It’s like detective work,” Kash said.

Woo added; “In ‘Murder on the Orient Express,’ the actors must create a world that the audience doesn’t see, that is very rich.” The script is rich enough to allow the actors room to delve into their characters’ backgrounds and “fill in the moments, you’re there” with everything that’s happening or being felt off stage.

In her case, Woo’s character, Mary Debenham, is hiding a secret so, in a sense, Woo the actor is playing a character who herself is acting. It feels like “a play within a play,” she said.

This would be music to the ears of director Morris Panych: “Working with an ensemble is a matter of creative trust. I don’t come into a room with everything planned. I see what the relationship is like with the actors.”

The challenge for Panych, in both a figurative and literal sense, is that “Orient Express” takes place on a train. There are a lot of moving parts, with actors moving between cars and rooms as they navigate between scenes. The grease leading to a frictionless work and rehearsal space was to allow “the actors to contribute in a creative way,” he said.

In “Express,” Panych is creating what he called “a moving, kaleidoscopic space, where the audience can experience the vertiginous emotion of the piece and actors can create something that is twisting and unravelling at the same time.”

The twist is, of course, part of the mystery, as is the unravelling, which comes down to Poirot’s concept of crime and punishment, and audience members’ expectations, if they’re familiar with what is perhaps the most famous of Christie’s 66 novels and 15 short-story collections.

Woo said it is like playing to two different audiences, one familiar with “Express,” the other not so much.

Panych doesn’t see familiarity with the work — knowing the ending — as much of an issue. “I don’t care if the audience knows the end. Most people think they know, but they really don’t know. It’s like ‘Hamlet.’ It’s just as entertaining (if you know it). You’re watching for different things.”

Like Woo rereading “Express” or Nancy Drew (she and her mother still visit used-book stores to find volumes to fill in particular Drew editions): One goes back and looks for the clues missed along the way.

In revisiting the work, Kash said he found references to many of the physical and social restrictions in 1934, when the novel was written.

“Men were just leaving the army and women had just left their corsets. It relates to what’s going on in the rest of the world” with resonance today. There’s “more social comment than meets the eye,” he said. Like in Shakespeare, where “they don’t treat the kings as special. They fart, they cry; they’re idiots.”

We live in a Trump world, he said; but that can be taken down because of that social conscience.

“People are comforted by someone seeking justice,” Panych said.