On Sydney’s hottest day in two years, the 199 from Manly has no air-conditioning. The windows are sealed. The emergency exit hatch that must never be opened is open.

A red-faced mother with sunburn mimes ‘Oh it’s hot!’ to the contents of a pram, fanning her face, puffing her lips out and smiling. She has blonde hair topped with sunglasses, and pale blue eyes.

Another woman leans conversationally over the barrier to the cross-seats, and the mother replies with an American accent:

‘Ya. Hottest day of the year. I’m just …’ She pauses and drags her palms down sweaty cheeks … ‘We don’t have far to go.’ She’s out of conversation, and lifts accusing eyes as new boarders squeeze in - schoolboys with white shirts, black bags and no sense of personal space, or of anything much.

As the bus grinds on she makes constant maintenance probes and water bottle offerings inside the pram. Her face grows redder, her eyes more tired. No smiles for the baby now, just a silent, red and sweaty frown of concern. She yawns suddenly. Uncertain whether to roll her eyes or close them, she does both.

Many stops later she escapes, backing the pram down onto a sun-blasted footpath, and an older woman follows with a shake of the head. They stand together, close associates of some kind but not friendly. Or perhaps the 199 has leached them of the will to try.