Harry Potter met his two best friends Ron Weasley and Hermione Granger on his first ride on the Hogwarts Express. So far he has been on the train nine times- twice a year for each of his first five years at Hogwarts except once, in Harry Potter and the Chamber of Secrets when he flew with Ron in a bewitched Muggle car, which crashed on landing and escaped into the woods (The car later saved him from the gigantic spiders in the forbidden forest). After each school year, Harry was met by his uncle and aunt after getting off the train; even though they hate him very much, they have never failed to pick him up.
The Hogwarts Express is a steam train only in appearance and somewhat in function. The train is a magical device. It borrows its form and its intended function from real steam trains, but not the technology.