W     ith 7,172 stations and seventy-one thousand miles of track, India has one of the largest rail networks in the world. Roughly twenty-three million Indians ride these rails each day, from Baramulla in Jammu and Kashmir in the north to the tip of the subcontinent at Kanniyakumari in the south, and from Gujarat’s Naliya in the west to Tinsukia in Assam’s westernmost frontier, and everywhere in between. The Vivek Express from Dibrugarh to Kanyakumari—an 83-hour, 2,655-mile journey—is the longest non-stop route.

David Jennings is a writer and photographer from Oklahoma. Between 2012 and 2014, he logged more than three hundred hours traveling to the four corners of the subcontinent, riding in every class and sometimes sleeping near the toilets in the connector joints when he couldn’t get a ticket. (All photos © David Jennings)