After rewatching this trailer, I was surprised to find that it did in fact contain some, though very little, dialogue. In my memory, the only sound was the train. This means that the train motif, combined with the other visuals, was powerful enough to make a lasting impression. The dialogue certainly doesn’t detract from it and lets you know outright that the film is about an affair, but I believe you’d get most of that without any words at all.
I didn’t have any strong desire to see this film, but the trailer hooked me. Obviously the pairing of Kate Winslet and Jennifer Connelly helped, though the latter is criminally underused in the film, especially considering how prominently she’s featured in the preview. But all I knew about Patrick Wilson was that he was the guy from Hard Candy, a film I hadn’t seen at the time. (Actually, that’s still pretty much all I know about him.)
The idea of a train suggests a number of things: movement, change, speed, and most importantly, inevitability. Things are going to continue to barrel forward, and they only have one path to take. If another’s path happens to be headed towards your own, a collision is unavoidable.
That goes for both the film’s two lovers and their respective spouses (more so Connelly, since Winslet’s husband isn’t shown in the preview.) At some point Winslet and Wilson are going to unite in something that, while horrible and painful and destructive, couldn’t really be avoided. And together, they will create a new path, one that will eventually lead to an even worse crash with more consequences.
The fact that you do not SEE a train for much of the time adds an ominous tone, especially when the sounds are featured over shots of such quiet moments as a family meal and poolside lounging. It hints at some energy lying right under the surface, which in the film manifests itself first as a desire to give into temptation, and then as a secret that desperately needs to be kept.
I agree with the sentiment of unfortunate destiny up to a point, or rather, after a point. Perhaps after reaching a certain moment in the relationship, their affair is unavoidable, but they made the initial choices to reach that point in the first place.
Regardless of your opinions on the central theme, it’s a great way to hook you and leave you wanting to know more. After all, everyone loves watching a train wreck.