There had been fears, based on the significant debate that has occurred over the best way to get the track across the lake and from there down to Woden, that jurisdictional squabbles could cause significant cost blow-outs and delays.

Mr Morrison's reported assurances the two governments would work together to overcome the not insignificant regulatory challenges that will need to be sorted out in order to connect Woden to Gungahlin and the various points in between may go some way to allaying those fears.

Because the parliamentary triangle is the responsibility of the National Capital Authority, a federal body, there has always been ample room for cross-jurisdictional confusion and even the possibility one government might try to play political games with the project at the other's expense.

That now seems unlikely to happen given Mr Barr's favourable commentary on recent talks between himself and the Prime Minister at the recent Council of Australian Governments meeting.

"I welcomed the Prime Minister's positive comments reaffirming his support for the timely approvals of stage two of light rail in Canberra," Mr Barr said on Tuesday.

"This endorsement is encouraging and it will certainly ... help create more jobs in the ACT."

Jobs, of course, are extremely important. They are also one of the reasons the Reserve Bank has been urging Mr Morrison and Mr Frydenberg to dig deep and build a few roads, dams and other desirable bits and pieces of national infrastructure in order to deliver economic stimulus.

Promises from the Prime Minister to work with the ACT government to fast track already committed spending are also good news for a jurisdiction in need of investment.

Wednesday's timely announcement of $1.8 million in federal government funding to improve safety along Southern Cross Drive won't only save lives; it will also create employment opportunities for some Canberrans while helping keep others in work.

Apart from the $500 million commitment to the Australian War Memorial expansion which is going to take a decade to unpack, the ACT hasn't seen much in the way of federal largesse since the 2013 election. While existing commitments are welcome, there is more the federal government could be doing to invest in the nation's capital.

If anything, given cuts to the public service and the Coalition's desire to export Canberra jobs to the regions, we've gone the other way.

Mr Morrison, despite his reported support for stage two of the light rail, has stopped short of matching the $200 million Mr Shorten pledged to provide in the event he had won the election.

While the assistance on the administrative and appeals front is not to be sneezed at, some cold hard cash would reduce the amount Canberra's ratepayers need to pay.

Such a combination of federal support and federal funding would almost certainly guarantee stage 2A, the Civic to Commonwealth Park leg, would deliver light rail from Gungahlin to the lake by 2024.

On the subject of stage 2A, while the ACT government is correct in saying it would be unwise to release cost estimates before the commercial negotiations are complete, it should commit to full and open transparency on the business case and the expected cost once the talks are finalised. Doing so would go a long way to building community support.