In front of our campsite the river runs with a hollow rushing sound. We can hear car horns echoing through the highway tunnel above. We gear up and head toward the water, sliding over the huge round bone-white boulders, tripping through fly-fishing line strewn like dental floss.

It turns out that the narrow, precipitous train trestle is David's destination: it strikes him as the perfect place to smoke and brood over his advancing age. I follow him half-heartedly up the gravel embankment and stand gazing down the convening tracks as he scrambles onto the thin girders. Far below, river water veils boulders, swirls into dark turquoise pockets.

At times like these I worry both about David's overconfidence in poetic imagery and my own propensity to worry. I wonder which is worse. I put my ear down on the rail to check for vibrations and come away with a big grease tattoo on my cheek. A strange thought pops into my head: What if we had kids? Jesus. Why would I think such a thing? Because David strikes me as immature, maybe underprotective?

Once the thought is in my head I have a hard time pushing it away, and I stand perfectly still for a moment. The river's rush is like the sound of electricity, a blanketing white noise. Above it I can hear the shouts of the three kids camping next to us.

Dark drops of rain spatter the gravel and David comes up behind me, ready to head back. As we hop along the oily ties he talks nostalgically about playing on tracks as a kid. I ask him if he ever left pennies to be squished – it's something I've always wanted to do. We dig in our pockets and lay the copper offerings out across from strategic gorse bunches. David rubs the grease on my cheek. Rain runs down my neck and I shiver.