I'm guessing that you've got a little more time to watch railway videos on your computer this weekend, so here's a longer than normal film featuring Michael Palin, who is every bit s nice a bloke as you think, introducing some BBC clips.
There's a lot of Betjeman of course and you may well have seen this bit before, but either open some more chocolates and stick with it, or fast forward as he's not the only star.
Palin has been well briefed and comes across as knowing his stuff enough to read the script like it's not a script. He also fits the "look" required for this slightly nerdy subject. For a change, there will be no fast-forwarding an idiot presenter!