I love the very characteristic way Jack makes his entrance into the film. As the train disappears into the distance, we see Jack's truck driving towards us, backfiring, the engine obviously in need of a tune-up. It lumbers into its parking place, backskids and then stalls. Jack gets out angrily, kicks the tyre and mutters 'S**t', before turning to notice Ennis standing there.
Even before we see Jack, we get the impression that he's the one who will be generating the humour in the film.