[1] In the early 1980s, Cercanías services started gaining importance in cities like Madrid and existing units, essentially Renfe Class 440, began to become insufficient.

This was materialized in a prototype, Renfe Class 445, built in 1984 and tested in Madrid and Barcelona's networks until year 1990.

After this, Renfe Class 446 and 447 started their manufacture process in 1989 and 1992 respectively, the second of which added some improvements to the original model.

The only visually perceivable difference between 446 and 447 is that, in the first, letters "R" and "M" in the numbering system are displayed red and white respectively, while in 447, they're both yellow.

Class 447 units use 3 kV DC overhead catenary line electric traction.