This is one of the special features on the companion disk for "Once Upon a Time in the West"--the Sergio Leone epic film from 1968. However, unlike the other special features that were excellent, this short documentary was, frankly, pretty terrible. This was partially because it was so short and partly because the style of the documentary didn't make things any better--and as a result, it was all pretty dull and unnecessary. The film is to be about the impact of the railroads on the American West. However, the discussion was just way, way too short--and relating all this to the feature film was not done effectively. And, to make it worse, the narration is spoken in a very stilted manner and projected a paragraph at a time on the screen--with the action during most of this in a small window. Why? I dunno--but it seemed weird and unnecessary.
By the way, my complaint is NOT about having the narration captioned. My daughter is deaf and I am hard of hearing, so I appreciate captions--just not paragraphs at a time. And, more importantly, it just wasn't interesting at all. My advice is see the three-part documentary on the disk and skip this short and not particularly good one.