Well this right here is my idea of filmic excellence.
Set in a bustling train station in 1950s Cairo, it transcends its setting to tell a thoroughly engaging story. The director is like an anthropologist who is at once knowledgeable about how the characters and their situations are wholly peculiar to 1950s Cairo, and at the same time fully aware of how their stories and struggles are undeniably universal. At times the film flirts with romantic melodrama with its central love triangle. At other times it feels like a slice of classic Cinema Verite in its almost documentary-like rovings around the lower classes who make their living at the station. But at its core, it's nothing but an early psychological thriller about love and obsession (which, as a shot near the end emphasizes, can perhaps be seen as two sides of the same coin).
Made some sixty years after the Lumiere brothers filmed The Arrival of a Train at La Ciotat Station, it's hard to imagine that those early film pioneers would be anything less than impressed with what the art had become in the hands of this Egyptian storyteller. And sixty years after Bab El Hadid (aka Cairo Station), it's still hard to imagine a more enjoyable movie being set in a train station.
Calling any movie one of the greatest of all time is a vacuous epithet that ignores the subjective nature of enjoyment. That said, I can definitely see where those reviewers who call Cairo Station one of the "greatest of all time" are coming from.