The ATS system used on the former ATSF lines in So. Cal. is an "intermittent" system, with inductors only installed at signals, and a few that are steel bent to the same shape that give a restrictive indication often seen at the end of territory, approaching a slow curve, etc.

There are a variety of different reactions that any enforcement can be designed, anything from a warning and straight to emergency to a full service reduction (either straight away or split). There hasn't really been a true "common standard" for locomotive brake systems between railroads, but the "final" version of the proposed train control will probably be interchangeable between most railroad operations.

The whole ECP issue will bring more problems. It looks like the next generation of engineer's will be servants to electronic devices who know better than they do how to run a train.

Just my opinion....