Sierra de la Culebra line
The Sierra de la Culebra Line is a Spanish railway line that connects Madrid and Zamora with Galicia . It was opened in 1959 after forty years of construction, which was often interrupted, and is one of the boldest mountain railways in the world.
The 452 km long, still not electrified route begins in Zamora and runs along the Portuguese border over the Sierra de la Culebra to Ourense and from there via Santiago de Compostela to A Coruña . After the Belgrade - Bar line , it is the second-richest railway line in Europe with 182 tunnels . 78.2 km of the total route alone run through tunnels. Among the numerous viaducts , the 481 m long and 84 m high Esla Viaduct is the largest, while the 219 m long and 86 m high Ulla Viaduct is the highest.