Trains take a long time to stop even at moderate commuter train speeds because they are so heavy, let alone high speeds of 300km/h+.

At least one of the failures here is that the dispatcher authorized such a high speed, in other systems I am familiar with, generally the procedure with a signal fault is to crawl at a speed such that the train can stop in line of sight distances.

In fact, that is the Spanish protocol, which for some reason was bypassed by dispatch even after the train driver had questioned it:

> Under normal protocols, the driver would be expected to continue moving at a maximum of 40km/h according to their line of sight, and not at normal speed on a track designed for speeds of up to 200km/h.