Emma Donoghue is a master of locked room fiction. In her 2010 blockbuster, “Room,” a mother and son are held captive in an 11-by-11-foot shed for years. Within those walls, Donoghue created an expansive world by turns joyous and disturbing. The author’s riveting new novel, “The Paris Express,” is similarly contained though the effect is vastly different. Here, her characters are strangers on a train, confined together aboard Engine 721, bound for the City of Light. To all its passengers but one, this is a routine commute: a few hours during which to relax, exchange gossip or perhaps even fall in love.

“The Paris Express” by Emma Donoghue. Summit. $26.99

For 21-year-old Mado Pelletier, however, the trip is a long-awaited chance to even the score. Having been radicalized by her poverty and her late father’s obsession with the capitalists “to blame for the sufferings of the working classes,” she wonders why “no one else in France thought of copying the Irish in London and setting off a bomb on a train?” She researches how to construct a homemade version, surreptitiously collecting the necessary components, then fits the final product into a lunch pail and brings it aboard the Paris Express on a day she knows it will carry members of Parliament. Simmering with resentment, Mado’s willing to sacrifice her own life — and take the innocent with her — so that “the powers that be will know that nowhere is safe.”

While this storyline wouldn’t be out of place in 2025, Donoghue, an adept writer of historical fiction, has set the novel in late 19th-century France, where the industrial revolution has displaced workers and produced a hand in glove relationship between government and business. For one, the six train companies connecting the country are state-owned but privately operated, forming a monopoly. Like French society itself, the railway cars are divided into rigidly demarcated classes. First-class cars are spacious and offer velvet upholstered seating, with “thick carpet underfoot, heavy lace-edge curtains, the door rimmed with gilt Morocco leather.” The carriage is “as intimate as a dinner party.”

On this day, its occupants include industrialists and their wives and daughters, as well as prominent politicians en route to the capital for the opening of the National Assembly. The second-class accommodations are less luxurious but provide a modicum of comfort and privacy, whereas third class is a steep step down. Its quarters are cramped and drafty, with only backless wooden benches to balance on. Its cars are purposely positioned to absorb most of the coal dust, not to mention the brunt of the impact in the event of a crash. A train is the ideal vehicle for Mado’s mission, she reflects, as “a moving image of the unfairness of the long con of life.”

While Donoghue clearly intends “The Paris Express” as, in part, a social novel, it also has much in common with Agatha Christie’s “Murder on the Orient Express.” Like that 1934 classic, it showcases the interactions of a range of intriguing characters who don’t know one another. While there’s no Hercule Poirot gathering information and sharing it with the reader, we do get textured glimpses into the characters’ broader lives via multiple points of view. There is an aspiring female scientist — a “femme de couleur” named Marcelle — in conversation with Henry, a Black American painter; there’s a steely Russian named Blonska who dedicates herself to being useful, and is the closest we have to a heroine; there are two railway men stoking and steering the train who are also lovers. And then there’s Mado, “l’androgyne,” dapper in her tailored jacket and oiled-down hair, alight with rage. When will she detonate the bomb? The suspense gains steam as the train speeds from station to station.

Meticulous research has gone into the writing of this thriller, including into the real-life passengers on the original train. In the Author’s Notes, Donoghue writes that her inspiration was the Montparnasse derailment in 1895, which was presumed to be “another anarchist terror attack,” and later determined to be an accident. The occurrence generated massive media coverage, including many sketches and photographs of the scene. It was one of those images that intrigued Donoghue and led her to build this intricate tale.

Engine 721 itself is a character with its own perspective. “She is how the crew refer to the train, out of fondness but also to mark the distinction between her and them.” She suspects that she is in danger, “that this might very well be her last ride.” Powered by coal and water, “She is made of wood and metal,” Donoghue writes, “and her temperament is stoic.” She doesn’t “take it personally” that one of her passengers is plotting her destruction.

If the steam engine is an astonishing feat of engineering, so is Donoghue’s propulsive and thought-provoking 16th novel. The problems plaguing 19th-century France appear not so different from our own, and its people are startlingly familiar — the working class doing their best to eke out a living and, against the odds, leave the world “a little cleaner” than they found it. Not so for the 1 percent.

Which brings us back to Mado, who believes the only cure for inequality is “revolution.” We remain on the edge of our seats all the way to Paris, wondering whether righteous anger or human decency will prevail.

Leigh Haber is an independent editor, writer and publishing strategist who for 10 years ran Oprah’s Book Club.