The 145 million Euros that the Ministry of Public Works and Transport has announced for the maintenance and integral rehabilitation of the Pajares slope "are not enough to adapt this centennial passage for the transit of long and large tonnage trains, which are those that Asturias and its defiles need". This is the warning made by technicians who have analysed the state of the overhead wires and who also warn that a great part of its 65 tunnels need "in-depth" performances. "We should not only act on the gauges, but also on other aspects such as the radius of curvature", the experts consulted warn, strong defenders of maintaining the model of Diversion for mixed traffic of travelers and goods, as it was being executed until last Friday, when the Ministry of Public Works and Transport communicated that it was changing the plans to comply with the agreement signed between the PP and Foro. Vicente Luque Cabal and José Antonio Sáenz de Santa María, chairman and vice chairman of the Plataforma Tecnológica Túneles de Pajares (Pajares Tunneling Technological Platform), said that the pass "has already fulfilled its mission" and that it can not be considered as an alternative route.

The Pajares route has suffered numerous incidents of traffic in recent years. Thus, in February of 2015, a snowfall cut the way between Asturias and León during five days. This is something that would never happen in the Diversion thanks to the great 25 kilometers long tunnel that crosses the Mountain Range from the village of Los Pontones to Pola de Gordón. In addition, in September 2016 an Alvia that covered the itinerary to Barcelona derailed in the pass, in a section in which the speed was reduced to 30 kilometers per hour due to a fault in the way. Fortunately, the incident, which only had a slight wounded person, took place as the train slowly entered a tunnel, being squeezed between its walls. Barely a month later, a coal-loaded train covering the route from Aboño to Ponferrada also derailed in the first foothills of the pass. The locomotive's axle came off the rails when it was inside a tunnel.

Another notable incidence of the many recorded in the slope inaugurated more than 130 years ago by Alfonso XII occurred last January, when a breakdown in the catenary blocked the interprovincial route of Pajares during a whole day, affecting numerous Alvia and several freight trains.

According to the official figures of the Ministry of Public Works and Transport, the annual maintenance cost of the Pajares slope is 15.4 million Euros. To this amount we would need to add another large sum for the Diversion, since, according to the data given by the Ministry, one kilometer of High Speed amounts to 100,000 Euros per year, and twice as much in the case of the tunnels, which means an investment of between 8.5 and 10 million Euros each year.