Comment by tedggh

On Spain’s conventional and high-speed rail network, inspection frequency is defined by ADIF rules and EU railway safety standards.

High-speed lines (AVE): Visual and geometry inspections are performed daily to weekly using inspection trains and onboard measurement systems. Ultrasonic rail flaw detection is typically done every 1 to 3 months, depending on traffic and tonnage.

Source: ADIF high-speed maintenance programs and EU interoperability maintenance requirements.