i don't see where it says they should use gps alone. In fact it even mentions starlink in addition to gps.

>Even GPS + Starlink + 1 monitor (is that 50k€?) could have prevented this.

My reading on that sentence was that even a simple setup would have been sufficient to prevent this. Not that it should be the only thing.

My reading indicates, that "Even X could have prevented this." means that X is able to solve the issue on it's own. Otherwise X would in fact not prevent it.

- I don't think X would actually work, without actually eventually recreating part of the current railway control system, and the current rail control system alone already works better.

- I don't think another less reliable more costly safety system helps, when the current one already stated that there is a problem, and it was ignored.

>My reading indicates, that "Even X could have prevented this." means that X is able to solve the issue on it's own. Otherwise X would in fact not prevent it.

X on its own would have solved this particular crash, yes.

X + existing setup would solve this crash + all the other crashed the existing setup solves.