Across the harbour I see a fin slice water, enough to keep my gaze. I’m not expecting much today: it’s muggy, no seabreeze to speak of, the water silver still.

It seems to take only a second to cross the bridge when you’re not paying attention, but when you are, it feels like you have whole, multiple minutes. Precious minutes as the train takes you ever onwards and you’re waiting for another break in the surface of the water.

Don’t have to wait long today – another fin slice then a leap, so quick and far enough away that you retain only the perfect image of the arched dolphin, dark against the water. And then, once you’ve rounded a bend and your view of the water is nearly at an end, three more –  one dolphin after the other crests the water ever so slightly, barely breaking its silver surface.

Another leap, quick and glimmering, brief suspension above the surface, belly glistening bright.

From the viewpoint of a train carriage of commuters at the end of a hot day, between car carrier and cargo vessel, between north wharf and south, you have this: tiny, distant silver dolphin bodies above silver harbour surface.