every train (metro or hi speed) must keep low tech phone communication with the next train (behind).

maybe 1 conductor is too busy for that, then get a co- or assistant sitting alongside, main task?

keep contact with the following train! say the rule is every 5 min the guy must tell colleague behind "everything ok, roger" and got answered "copy that". if the contact got lost that means sth wrong and the next train must decelerate, prep to stop, and tell the next next train!

say? how simple is that, even though i am layman, i believe it can be easily done.

not that i don't like hi-tech, i just don't like to put eggs into 1 basket, a so-called high tech one every train controlled by a central office.

old saying said sly rabbit got 3 homes. maybe you heard the recent story that experts managed to hack into advanced cars controlled by computers.

our civilization are more and more advanced, but many times simple and old ways still have merit.

easy does it, simple does it