Critical Railway Braking Systems Open to Tampering

Researchers have shown that signalling used by some rail systems can be spoofed, potentially enabling dangerous tampering with train braking. In Spain, the ASFA system dates back to the 1960s, and TechFrontiers’ Gabriela Garcia and David Melendez demonstrated how a hacker could manipulate the signals with minimal gear.

They tested their approach with a crude, handmade replica using copper wire, a recycled food can, capacitors from a power supply, and a cheap signal generator, and they say the device could halt a moving train or issue false speed commands. The researchers discussed their findings ahead of an upcoming Black Hat Europe 2025 presentation in London, noting that even basic knowledge could enable manipulation of balises and corresponding signals.

Modern systems such as ETCS are more digital, increasing both functionality and risk, including digital jamming, spoofing, and data theft, but the researchers emphasise that securing these systems would be a substantial undertaking. The article, dated 19 November 2025, underscores the ongoing challenge of upgrading legacy railway safety mechanisms while highlighting that analog ASFA remains vulnerable in many systems.