Auden wrote the poem, but the two voices heard in the film belong to John Grierson ('Down towards Glasgow she descends...') who was head of the GPO Film Unit, and Stuart Legg (who does everything else).

Thanks for that correction. I should have known better, having written a small thesis on Auden in another lifetime & knowing his voice! Yet his contribution to the film was more than just a poem; cf. Marsha Bryant, "Auden and Documentary in the 1930s" (1997) and www.theguardian.com/books/2007/d....

Stamp of excellence

Night Mail, about the London to Glasgow postal train, is a classic of the 1930s British documentary boom, with contributions from Auden and Britten. Blake Morrison marvels at its poetry and populism