The Pajares pass in the north of Spain is one of the most impressive mountain lines of Europe, with more then 60 tunnels, loops and some viaducts. In fact it is more a ramp, with a grade of 2 %, climbing from sea level in Gijón via Oviedo and over the Cantábrica mountain range to the inner spanish highland. The highest point is 1270 meter a.s.l. at the south portal of the 3072 meter long Perruca tunnel below the Pajares pass. The mostly single track line in the iberian broad gauge of 1668 mm (5 ft 5 21⁄32 in) was built between 1864 and 1884 and electrified in 1924 with 3000 V DC. The variable gauge Talgo train of the 130 series "Patito" is running as Alvia 4140 service from Gijón to Castello de la Plana, near Villanueva de la Tercia on the south side of the Pajares pass.
