Typically they will announce to the PCC (central control) that they sighted people in the tunnels. The next train that comes through the sector will roll at wal

Typically they will announce to the PCC (central control) that they sighted people in the tunnels. The next train that comes through the sector will roll at walking speed. If you haven't cleared out by that time and get seen, they stop all traffic on the line, and send in rail police from each side of the tunnel to find you.