Over the past couple years, I've been getting more and more into British railways, and YouTube is an endless source of amazing footage! Also, look up the Railway Roundabout series from the late 1950's into the early 1960's. There are compilations of each year out there on YouTube, and those are amazing!
Actually, I love that the UK will show railway documentaries on the BBC! Heck, there was even a great documentary on the history of model railways called, "The Joy of (Train) Sets"!
The one in the original post is amazing to watch. Thank you!