I've been been looking at a lot of photos showing BR in the 1970s - and so this excellent film from 1972 is really interesting. I like to think this is fairly recent, but it's nearly half a century old!
The railway was different then. Lots of lovely locos to spot and interesting rolling stock.
Overall, the tone is positive with many technological advances. This isn't quite what I remember (OK, I was 2, but you get the gist) from the period, but I suspect that the grimy, rail blue world coloured our perception.