Renfe Altaria is a train serive operated by locomotive pulled fixed train compositions built by the company Talgo. The trains are fixed compositions which are able to change their gauge width so that they can run on both normal and Iberian broad gauge tracks. Renfe uses them on services from Madrid to Algeciras, Alicante, Barcelona, Cádiz, Cartagena, Granada, Irún, Logroño, Murcia, Pamplona, and San Sebastián.
Picture from Barcelona Sants station 11.11.2011 by Ilkka Siissalo.

A view of the same Altaria train but from the other end, where a Siemens EuroSprinter locomotive of the class 252 was ready to pull the train towards Madrid. Altaria trains can run up to 200 km/h.
Picture from Barcelona Sants station 11.11.2011 by Ilkka Siissalo.

This old train was composed of fixed very short carriages. It was called Talgo III and it was the company Talgo's first generation of coaches with variable gauge width which allowed these trains to start from broad gauge in Spain and cross the borders to France and to run with normal 1435 mm gauge. Only the change of locomotives was needed at the border. These Talgo III coach sets were taken in use in 1969. The locomotive seen here in front of the Talgo III coach set is of Renfe's class 350. There were only four of them. It was a locomotive type with just one driver's cab. They were built in 1949 by American Car & Foundry Co.
Picture from Barcelona Sants station in 1980 by Adrian Gray.