The last time the Tay Bridge Disaster featured as part of A Play, A Pie and A Pint was in Gary McNair’s McGonagall’s Chronicles. The titular star of that piece wrote what is, by reputation, the world’s worst ever poem, about the event of 1879, in which an estimated 75 people perished in the waters of the Tay when the bridge collapsed, taking the train they were on with it. Thanks to McGonagall’s work, the disaster now has an element of comedy attached to it in popular imagination. Peter Arnott’s The Signalman puts paid to that. McGonagall’s verse does get a brief airing to a knowing snigger from the audience. Otherwise this is an involving and deeply atmospheric true horror, a reminder of how the industrial genius of the Victorian Age came with a side order of terrors unimagined.

Tom McGovern plays Thomas Barclay, signalman for the south side of the bridge. He’s 64 now and the year’s 1919, but that dark night of 40 years previously has ever played on his mind. It’s Barclay’s story that we hear, but under Ken Alexander’s direction we are made to feel so much more. The enveloping darkness of the stage – an end-on set-up today, not the usual thrust configuration – seems depthless, thanks to Ross Kirkland and Chris Reilly’s clever lighting, and the sound (Jon Beales and Andy Cowan) subtly blends music into the sounds of worsening weather. You’re listening to Barclay and watching him peer out of his signal box when you notice that wind is still blowing. It makes you want to pull your collar up around you and hug yourself tight. It looks awfully cold and fearfully lonely down where he is.

Barclay relives the inquest and we feel the claustrophobia. The spotlight clings tight to the man in the dock and his solitary voice echoes through the silent courtroom in answer to the judge’s questions.

Then he relives the moments leading up to the accident – handing a baton to the train crew as they slowed to get permission to cross, watching the train out onto the bridge, seeing the lights disappear, and then the wait for the signal from the north side…

…that never comes.

It chills the blood. Barclay, realising something’s amiss, has to stop the trains behind, then venture out, alone, blinded by the dark and rain, on to a skeletal bridge and into endless blackness, not knowing if anything awaits. This is still an analogue world. Technology’s evolved enough to create a new, horrible disaster like this but not enough to provide any aid for dealing with it. Barclay’s only response is physical – crawling, petrified, to see what’s happened. It doesn’t bear thinking about.

McGovern’s Barclay is the right man for this piece. He’s no hero, and that’s no criticism. He’s an ordinary man – pleasant, personable, uncomplicated. That turns out to give him the ideal perspective on the disaster. While the legal profession look for someone to blame, and the clergy assign it to the judgement of God, he just sees normal folk and purposeless death. That void into which they fell – it’s an existential metaphor.

On that point, the play could be accused of overstretch. It’s been a chilling forty-five disaster play and very effective with it. To laden it with extra layers of meaning in the final minutes – there’s also another reason for Barclay’s introspection it’d be wrong to spoil – is arguably overkill.

Equally though, it gives Barclay that extra dimension. He’s not just narrator, he’s a participant. He’s been shaped by it. You don’t witness what he himself describes in apocalyptic terms and escape from it with worldview intact. Some sense of what conclusion Barclay wants to draw is therefore necessary. Whether it attempts too much on that score is a moot point, but one that doesn’t detract from this haunting short play.