A 23-year-old university student in Taiwan is currently out on bail following an investigation into a communication breach that brought the nation’s high-speed rail network to a temporary standstill. The individual, identified by the surname Lin, is a radio enthusiast accused of interfering with the terrestrial trunked radio (TETRA) system used by rail staff.

The Signal Disruption

On April 5, three high-speed trains were halted for approximately 48 minutes after a “General Alarm” signal was broadcast at Taichung Station. This specific signal is typically reserved for emergencies and is triggered by specialized equipment used by station personnel to communicate with drivers. Following standard safety protocols, the emergency response plans were activated, requiring all nearby trains to stop manually.

The Investigation and Vulnerability

Because the equipment used for these signals is not available to the general public, investigators from the Major Criminal Cases Unit initially suspected internal misuse or stolen hardware. However, after ruling out staff involvement, detectives shifted their focus toward external interference.

The investigation revealed that the disruption was likely caused by a radio cloning technique. Lin allegedly used software-defined radio (SDR) equipment purchased online to capture the specific frequencies used by the rail network. By connecting a radio to a laptop via an SDR filter, he was able to replicate the transmission code of the General Alarm. This allowed him to trigger the emergency system remotely, making the signal appear as though it originated from an official handset.

Legal Consequences and Seized Hardware

Police conducted raids on Lin’s residence and workplace, seizing seven radio devices, a laptop, two smartphones, and specialized filters. Authorities characterized the method as rudimentary but effective in exploiting vulnerabilities within the existing communication infrastructure.

Lin was arrested on April 28 and subsequently released on NT$100,000 ($3,183 USD) bail. While the disruption did not result in physical injuries, the case has been treated as a significant threat to transportation safety, prompting a review of the security measures protecting the country’s transit communication networks.

Filed in . Read more about Radio, Security, Train and Trains.