Sol mainline station, Madrid

Sol station was on the original Metro line 1 (100 years anniversary this year). I knew it well from the 1980s. When I came to teach in Madrid 25 years later, I wasn't aware that it had also become a mainline station and a new line linked the termini of Chamartin in the north and Atocha in the south. If I'd been aware of it I could have saved 100s of hours of unpaid travel time! DOH!