everlasting staircase

(UK) An escalator.

A charmingly old-fashioned British term for an escalator, popular in the early twentieth century before 'escalator' became the dominant word. The phrase captures the wonderment felt by people encountering this technology for the first time — it's just a staircase that moves, which is both accurate and somehow more magical than the technical term. Still occasionally used today with a deliberate nostalgic or whimsical tone, especially by older speakers or writers going for period flavor.

a flight of stairs, especially out of doors.

(chiefly, British, rare, or, dated) A flight of stairs.