The audio begins with the familiar metallic clanking and screeching of a city subway, a locomotive beast gliding through the labyrinthine underground network. The low hum of the metro grows louder, echoing off the tunnel walls, intensifying as the train draws near. The unmistakable rhythmic rumble of the subway car on the tracks resonates, a pulsating heartbeat of the city. The sudden, sharp hiss of the brakes punctuates the steady drone as the subway slows to a halt, the doors glide open with a mechanical whir. The hustle and bustle of passengers boarding and disembarking fills the air, punctuated by the occasional murmur of conversation and the shuffle of feet. The doors close with a distinct, echoing thud, followed closely by the automated announcement that filters through the speakers, guiding travellers to their destinations. The subway lurches forward, the powerful roar of the engine revving up again, and the journey continues, transporting city dwellers and visitors alike