Drafting of the construction project and execution of the works for the renovation of the class A3 protection system at level crossings PK 320/705, 321/326 and 348/187, the improvement of protection to class A2 at level crossings PK 324/026, 333/830 and 356/476 and the improvement of protection to class A4 at level crossing PK 333/423 on line 770 on the Oviedo-Infiesto section in Asturias.