Signalling, especially in another country, is not my specialty... But stateside (where tech can range from 2026 latest to akin to 1926).. there would have been a trackside signal that the moving train would've had to ignore... On top of the dispatch/comms screw up. I, like you, would have assumed there'd be some positive control preventing the trains from being on the same section of track or at least at high speed. Hopefully this will spark safety initiatives to improve signalling and train control.