From Strangers on a Train to even Mission: Impossible, there’s something about trains that has made them a staple of the thriller genre. Airplanes have a foothold as thriller material (Flightplan, Red Eye), but trains continue to hold the monopoly, as Kenneth Branagh’s upcoming adaptation of Murder on the Orient Express and this weekend’s The Girl on the Train prove.
Maybe it’s the combined sense of claustrophobia and powerlessness that make trains prime fodder for mysteries and thrillers; they handily bring a group of characters together in a confined space from which they won’t be able to escape until they reach the train’s destination, or jump off (inadvisable). (See: why there’s a subset of thrillers set on planes.) There’s also a certain blindness that comes with having to move from car to car instead of being able to survey a single room. Take Snowpiercer, for instance: the entire story takes place on a train. The cars of the train house different “classes” of people, with poor passengers crammed into grim cars at the tail end, while the rich occupy opulent cars towards the front. Secrets begin to reveal themselves as the characters work their way up, and while they have the basic economy class, business class, first class structure to guide them, that’s no guarantee as to what they’ll find when they break through to the next car. The same goes for Train to Busan, though in that film, the characters are forced to move back and forth instead of propelling themselves relentlessly forward. As zombies overrun the train and the core group of survivors fracture, their struggle to survive and reunite becomes more and more difficult as the zombies move, too, and their lines of sight remain restricted by the windows between cars.
Even in films with less brutal odds, the confining nature of trains ramps up both, mystery and ambiguity. Murder on the Orient Express is the most well-known example, as a passenger is murdered on board the train and Hercule Poirot attempts to solve the case before they reach their destination. Similar stakes are employed in Age of Shadows, South Korea’s submission this year for Academy Award consideration. The movie’s centerpiece is a game of cat and mouse between spies as set on a train. A contest of wits and craft that, thus far, has spanned continents, a la Tinker Tailor Soldier Spy, is suddenly confined to a handful of train cars, where space is at a premium and there are precious few ways of relaying information safely, especially with a mole in the mix.
It’s this kind of ambiguity that The Girl on the Train capitalizes on. Initially, we are only afforded fleeting glimpses into characters’ lives, just as Rachel only sees bits and pieces of the people she passes every day on the train. Putting those pieces together, not to mention filling in the gaps, requires going car by metaphorical car with no safety net, each compartment shedding a little more light into the next.