Being a passenger in this vast country is ‘a full-blooded immersion in the local’, says the novelist whose latest protagonist is lured by the romance of the rails

I carry my train journeys in my bones, the juddering song of the Indian rail. Our first prime minister, Jawaharlal Nehru, famously likened India to a palimpsest, no layer quite effacing the one that went before. That’s how I think of Indian railway journeys. They inscribe on the mind our fellow travellers, our ways, our thousand languages, our landscapes, our climate.

I think of a rail journey I made in 1998 – that brutal summer of nuclear testing – setting out from Mumbai, in an ordinary three-tier sleeper, for Dehradun, 1,000 miles (1,600km) north. The frazzled train fell off any semblance of a schedule. The voyage grew longer, past 50 hours; hotter, past 50C. I remember the metallic burn on the window grilles; the hot, killing wind that blew through them; the sizzle of water drops splashed on the face when theyhit the uncovered platforms in the heart of the country; the melt of my rubber soles. A fortnight later, having trekked to the mouth of a tributary of the Ganges, completing my expedition from the Arabian Sea to a Himalayan glacier, it was possible to look back on the rail ordeal with affection.