AVE, an acronym for (literally, "Spanish High Speed" but also meaning "bird" in Spanish) is a high speed train that can achieve speeds of up to 300 km/h on dedicated track.

Unlike the rest of the Spanish broad-gauge network, the AVE uses standard gauge, permitting direct connections outside Spain in the future. All AVE trains are currently operated by RENFE, the Spanish state railway company, although it is possible that private companies may be allowed to run lines in the future.

Construction of a high-speed line connecting Madrid and Barcelona is underway, with the initial section from Madrid to Lérida, via Zaragoza, opening on 11 October 2003. Completion of the line is planned for 2008, with the line reaching Tarragona in 2006. When completed, the Madrid-Barcelona line should be one of the world's fastest long-distance train in commercial operation, with trains billed to reach a top speed of 350 km/h and covering the 600 km between the two cities in 2.5 hours.

Although until 2005 both Siemens and Talgo/Bombardier train sets have consistently failed to meet scheduled speed targets, in a test run during the homologation tests of the new S102 trains of Renfe, a train-set Talgo 350 (AVE S-102) reached the speed of 365 km/h on the night of the 25th to the 26th of June, and on August 2006 a train-set Siemens (AVE S-103) reached the highest top speed ever in Spain: 403,7 km/h. AVE trains in Madrid-Lérida line have begun to operate at 250 km/h on May 19, 2006. RENFE claim that by the end of 2006 it should be running at 280 km/h.

In this context, one should note the highly critical report by the consulting firm KPMG. The report was commissioned by ADIF (Administrador de Infraestructuras Ferroviarias) at the behest of the Ministry for Public Works (Ministerio de Fomento) on June 23, 2004. KPMG's experts pointed to the lack of in-depth studies and over-hasty execution of works as the reasons underlying the major problems dogging construction of the AVE line.

It is forecast that the AVE will substantially replace air traffic on the Barcelona - Madrid route (in the same way that the Eurostar has on the London-Paris/London-Brussels routes and France's TGV has on the Paris-Lyon route). In fact, more than 80% of travellers between Madrid and Sevilla use the AVE, and only less than 20% the airplane.

Construction of a segment to Valladolid, extension of the Sevilla line to Málaga, as well as similar extensions of the system to Valencia and Alicante are also underway. Connection to the French TGV network is also planned, at either La Jonquera in Catalonia or Irun in the Basque Country. Further expansions to Galicia, the Basque Country (including the so-called Basque "Y" connecting the capitals of the three Basque provinces) and Portugal may eventually be built.