There must be a PO present at the Worksite for the period of the work.
A PO must:
get the TOA;
make sure that work in the Danger Zone does not begin before the required safety
measures are in place;
be responsible for the Protection of Workers from Rail Traffic;
make sure the Tracks between Worksites and protecting Locations remain clear of
obstructions;
make sure that Worksites are protected against the Unauthorised entry or exit of
Rail Traffic; and
tell Workers about the Locations of Safe Places