Why is every scene needlessly long?
Simply bad editing. There's nothing interesting about watching the slow unhinging of a train car with repeated cuts of the same scenario with each apparent buildup being nothing of the sort, sometimes including editing's version of a strobe light for effect or run on scenes of laughter. Add this commentary to many scenes throughout the film. It's pointlessly overlong. If edited down, it'd be a typical, decent action flick. I wouldn't even consider it a "western", but an ok action movie that follows Holden's half acting job too much.