What track gauge is used by Spain’s AVE high-speed railway lines?

Spain’s AVE high-speed railway lines use 1,435 mm standard gauge.

This gauge differs from the 1,668 mm Iberian gauge used by much of Spain’s older conventional railway network. Building new high-speed lines to standard gauge allows direct technical compatibility with neighboring European high-speed systems.

The AVE network expanded from the Madrid–Seville line into a large national system. High-speed trains can therefore operate on dedicated lines while conventional services continue using the older broad-gauge network.

Spain also has variable-gauge trains and gauge-changing equipment, which can create confusion. Those trains are designed to move between networks; the dedicated AVE high-speed infrastructure itself uses standard gauge.