Castilla y León has an extensive rail network, including the principal lines from Madrid to Cantabria and Galicia. The line from Paris to Lisbon crosses the region, reaching the Portuguese frontier at Fuentes de Oñoro in Salamanca. Astorga, Burgos, León, Miranda de Ebro, Palencia, Ponferrada, Medina del Campo and Valladolid are all important railway junctions.

Railways operate in several different gauges: Iberian gauge (1,668 mm (5 ft 5+21⁄32 in)), UIC gauge (1,435 mm (4 ft 8+1⁄2 in)) and Narrow gauge (1,000 mm (3 ft 3+3⁄8 in)). Except for some narrow-gauge lines, trains are operated by Renfe on lines maintained by the Administrador de Infraestructuras Ferroviarias (ADIF); both of these are national, state-owned companies.