A Taiwanese university student disrupted three high-speed rail services for approximately one hour using low-cost software-defined radio equipment, exploiting unauthenticated RF-based signaling protocols, including a system that had not rotated cryptographic keys in 19 years. The incident demonstrates that legacy OT environments in critical transportation infrastructure present a measurable, low-barrier attack surface that does not require nation-state resources or insider access. For security leaders, this is a signal: the same RF authentication gaps exist across rail, transit, and industrial control environments globally, and the cost of basic RF injection equipment has fallen to commodity hardware, creating a measurable barrier-to-entry reduction for adversaries with technical knowledge and physical proximity to the target infrastructure.