Dive into a fascinating conference talk that uncovers the mystery behind malfunctioning Polish Electric Multiple Units (EMUs). Explore the inner workings of train control systems, follow the reverse engineering process, and discover the unexpected "security" measures implemented by manufacturers. Learn about the technical aspects of modern EMUs, the intricacies of Train Control & Monitoring Systems, and gain insights into analyzing TriCore machine code. Witness how a seemingly complex issue was resolved by running a simple 'unlock.py' script on multiple trains. Suitable for those with a technical background, this presentation blends technical and non-technical elements to provide a comprehensive understanding of the investigation into suspicious train malfunctions.