One of these technical aids is ATC (Automatic Train Control). Each locomotive is equipped with ATC. The system was widely introduced from 1980 onwards.
Another system is remote blocking, which is a prerequisite for being able to control and monitor all train movements within a specific area from a remote signal box. Today there are eight train control centres in Sweden, from which almost all traffic is controlled and monitored. Announcements at stations are also made from these centres.