Originally classified by RENFE as 76xx and 86xx (the example in the photograph is number 7685), the 276 series was based on the FrenchSNCF Class CC 7100. The majority of the 276s were manufactured in Spain by various locomotive works, including CAF. Due to their Gallic origins, the locomotives were given the nickname francesa (English translation: French).
A total of 136 units were built during between 1956 and 1965, ten of which were modernised and classed as 276.2xx.
Since the 276 is a Co'Co' locomotive, it is equipped with two three-axled bogies – each of which is powered by three traction motors. This six traction motor configuration provides the locomotive with a total power output of 2,200 kilowatts (2,950 hp) and a maximum speed of 110 km/h (68 mph). Of the 136 examples produced, only 36 have been adapted for use in multiple unit operations: these are unit numbers 276.101 through 276.137, inclusive.