Sam bent into a crouch and laid a palm on the freezing rail. He could feel nothing, but Billy, they both knew, was the expert here.

‘Okay then. Bird or Queen this time?’

Billy was thoughtful. He turned the pale yellow dollar coin over in his mittened hand and made a decision. ‘I’m gonna go for the duck. You put yours Queen-up.’

He leaned forward and placed the dollar on top of the rail track as carefully as if he were handling a rod of plutonium. Sam, smiling, positioned his dollar a yard further up the track, the profile of the Queen of England facing the direction of the oncoming train like she knew what she was in for.

From here on the edge of town you could just make out the entrance of the tunnel, looming above the pines about three miles off, but Sam was damned if he knew how Billy could feel the vibrations of a train that far away. But he did, and here it came, the headlight emerging from the dark hole right on cue.

‘Stand back, Billy.’ Sam stretched a hand out for the boy’s.

‘Aw get real, Dad. That’s not gonna be here for at least five minutes.’

Sam stood up and looked towards the tunnel mouth, his hand still extended to his son. ‘No, you’re right, Billy boy. Why don’t you just lie with your head on the rail, and if it gets cut off at the neck your Mom and I see what we can get for your bike at a jumble sale?’

Billy sighed and rolled his eyes. He stood up and took the large offered hand, and together they moved back from the track. Still holding hands, they squatted on the snowy embankment ten feet away to wait.

From behind the forest came the deep, long, discordant hoot of the train’s horn, filling Silver Valley with a sound so thick it resonated in the spine as well as in the ears. Sam lifted his head like a cat smelling fish.

‘You like that sound, Dad, don’t you?’

‘Yeah.’

‘I like it too.’

Sam looked down at the face of the boy, framed now in his blue anorak hood, his black eyes glittering in a brown face. ‘What’s it make you think of, Billy?’

The boy looked solemn. ‘You.’

Sam was silent. He tightened his grip on the mitten containing his son’s small hand and resumed gazing up the track.

Billy smiled up at him. ‘Don’t you want to know why?’

‘Do I have a choice here?’

The boy giggled, a sound so sweet that Sam thought it might make primroses poke through the snow at their feet. ‘It just sounds like you, that’s all. I don’t know why.’

‘So I sound like a freight train horn, is that what you’re saying? Remind me of that if I’m ever tempted into a Karaoke Bar.’