Comment by rr2841

The machinist union requested the maximum speed to be lowered from 300 km/h to 250 km/h on multiple areas, the one where the accident happened being one of them. Both trains were driving under 210 km/h when the accident happened, so I don't think the "rattling" they reported was the issue.

As I mentioned before, this area was renovated last year, so attributing the accident to under-funding is highly unlikely. If the infrastructure happened to be the issue at the end, it might be because of different causes: eg. Planning the wrong materials for the amount of traffic / weather conditions / etc.

In general, when you talk about under-funding in the rail network it's often regional or small areas within the inter-city (larga distancia) and transport networks. High speed infrastructure is very well financed, it's not cheap to move trains close to 300 km/h.