overspeed protection has been standard on most national railways for decades

is there any reason they invented a new system (expensive and slow to rollout) vs. using an existing tried and tested one?

the main UK system (there are two) is nothing to write home about, but it is gloriously simple and was very fast and cheap to deploy: two metal transmitters live in the track bed coming up to a hazard, spaced such that they are 1 second apart at the maximum speed

if the train detector passes over both in less than 1 second then the brakes are triggered automatically

they look like this: https://en.wikipedia.org/wiki/Train_Protection_%26_Warning_S...