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Redalsa clarifies it only does electric welds

The steel firm Redalsa has clarified that it did not carry out the rail welding on the section where the Adamuz derailment occurred. It specialises exclusively in electric welding.

Redalsa clarifies it only does electric welds
Ultrasonic track monitoring vehicle used by Redalsa. © REDALSA.

Miguel Bustos | 28-01-2026.

Redalsa, the metallurgical company, has issued a statement to correct reports published in some media outlets.

Due to confusion, several outlets claimed it was the firm behind the alleged failed weld at Adamuz.

In the 23 January press conference (summary in this article), a journalist asked Adif president Pedro Marco de la Peña if Redalsa is an Adif-owned company. The executive replied: “And it is true, Redalsa does the welding. Redalsa is a company 51% owned by ADIF, a world leader in weld treatment and long rail production. And it is the company to which the contractor UTE subcontracted the ultrasonic testing of the 114 welds, which were later re-evaluated—34 of them—by another firm and team [AYESA].”

Founded in 1974, the company stresses it focuses solely on electric rail welding, or flash butt welding—a highly specialised process needing complex plant and stringent quality controls.

Redalsa boasts Spain’s only facility for forging long rails up to 270 metres via electric welding, plus mobile units for on-site jobs.

The firm has made clear it does not do termite welds, a technique relying on a high-temperature chemical reaction between aluminium and iron oxide.

The weld suspected of causing the Adamuz derailment was termite, done by Maquisaba, SL—another UTE subbie.

In contrast, electric welding delivers greater homogeneity, less variability, and tighter joint control, making it a safer, more stable method over its service life.

Termite welds like the one at Adamuz tend to show more failures in the early months if execution or cooling is subpar.

With this statement, Redalsa aims to quash mix-ups and ensure accurate info on its operations.

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