Since passenger trains are usually short and often have a wired bus) they don’t really need this system.

1) The brakes take an extra couple seconds to apply (note: this is only used on long trains… so stopping is over a minute anyway)

2) The emergency brakes apply. This is considered a safe condition, and for Positive Train Control is considered the ‘safe state’.

If someone tries to utilize this vulnerability, the EOT device will be shutoff. On the few tracks where it’s actually required, there are mitigations to still operate safely.

This would be really easy to annoy a single train crew. This would be really hard to do to geographically diverse trains.

Because it's an article about outdated systems. Radio-controlled systems built in the last ten years, and in the future, are all mandated to be encrypted.

Furthermore, very few passenger train systems are radio-controlled. Instead, just like cars and buses, control is decentralized to the individual vehicle, and automated based on feedback from the track. No feedback, and the train stops.