Ildefons Cerdà is a station in the Barcelona Metro network, served by FGC-operated L8, among other Rodalies Barcelona and FGC suburban lines. It's not properly in Plaça d'Ildefons Cerdà (a square in the Sants-Montjuïc district of Barcelona proper, but just next to L'Hospitalet de Llobregat) but in the L'Hospitalet part of Gran Via de les Corts Catalanes. It was built in 1987. It's also due to become part of future L10.
All of them operated by Ferrocarrils de la Generalitat de Catalunya:
Coordinates: 41°21′39″N 2°07′49″E / 41.3608°N 2.13028°E