 With the enactment of the "Transport Safety Investigation Act 2003" (Cwlth), the ATSB gained jurisdiction for rail incident and accident investigations on the Defined Interstate Rail Network (DIRN), consisting of the standard gauge track linking all major Australian mainland cities and ports.In December 2009, the Council of Australian Governments (COAG) agreed to adopt the ATSB as the national rail safety investigator, in conjunction with the formation of a national rail safety regulator.Commencing in January 2013, all Australian states and territories gradually adopted the scheme, with Queensland the last to join in July 2017.