Part psychological thriller, part social commentary, On The Tracks is a gripping two-hander exploring the secrets we do and don't choose to share. It's set in the break-room of an anonymous railway station; two shunters, Robert and Ted, are about to start their shift. If you don't know what a shunter does, then all will be explained. But this isn't really about the railways; it's about how little we truly know the people we see every day, and how unspoken forces can quietly buckle a mind.

We meet Ted first, sitting silently at the table, distant and distracted by something deep in his mind. His work-mate Robert knows what's wrong – at least, he thinks he does; and little by little, though unforced and convincing dialogue, we learn the painful back-story too. We discover fairly quickly that Ted's lost a son, the victim of an accident a few months ago. And we hear about the consequences: about the strain it's put on Ted's marriage, the dead silence that now pervades his entire life.

It's clear, though, that this can't be the whole story, and much of the tension comes from wondering which particular detail playwright Lucy Hayward is holding back. I made a few guesses along the way, but I was still blindsided by the ultimate revelation – even though, with the benefit of hindsight, I can see the dialogue contains some pretty obvious clues. It's a beautifully-executed twist, unexpected but entirely believable, the kind of thing that makes you want to watch the play again so that you can re-interpret what you've heard in the light of what you now know.

And exactly that experience – hearing, but not understanding – mirrors the script's main themes. Robert wants to help Ted: to encourage him to unburden himself, even in the face of truculence and antagonism. But when Ted at last begins to talk, Robert isn't really listening; he's distracted by his phone, by his radio, by problems in his own personal life. Both actors deliver a touching portrayal, optimistic in its example of how reserved men can reach out to each other… but they show us some depressing truths as well.

As a side note, On The Tracks is written to be accessible to both blind and sighted theatre-goers. If this kind of thing interests you, keep an ear out for the subtle scene-setting that Hayward works into the dialogue: witness for example how Robert describes Ted's jacket, under the guise of commenting on something else entirely. It's clever and unobtrusive, and I wonder if this example might encourage more playwrights to embrace the challenge of adapting their work this way.

Whichever way you experience it, On The Tracks is tensely written and powerfully performed. A few details of the staging could be improved – the lighting sometimes works against the actors, making it hard to read the expressions on their faces – but that's the only fault I can find with an intriguing and meaningful production. This is one show I won't be keeping secret.