About 6 mins (episode at start of last week included gold / silver mines & railway tunnels):
https://www.bbc.co.uk/iplayer/episode/b09s4kmy/great-american-railroad-journeys-series-3-20-la-jolla-to-san-diego
About 6 mins (episode at start of last week included gold / silver mines & railway tunnels):
https://www.bbc.co.uk/iplayer/episode/b09s4kmy/great-american-railroad-journeys-series-3-20-la-jolla-to-san-diego