Wellington wants to be in the Auckland loop?

Washington DC has its beltway, and hence the expression 'beltway politics' – a term that has been adopted, one hopes with irony, in Wellington, a town that can boast no less than Bowen St. It looks like high-level Auckland politics may in future be described as 'inside the (rail) loop'.
And, if you ever wondered what Gerry Brownlee sounds like when he's swallowing a dead rat and talking at the same time, then just listen to him on Checkpoint.
Jokes aside, what are the politics of the Key government's sudden volte-face in favour of helping to pay for the underground rail-loop in Auckland's CBD?
The time-line is leisurely in the extreme, with work set to begin in 2020 – by which time the present government will certainly have been booted out of the Beehive and consigned to the history books. So they have no skin in the game. And yet anyone acquainted with Auckland and, for comparison, with a city that actually has an efficient public-transport system (take Munich, for example) will know that this is a project that should have been completed last century.
So, what's the real agenda here?
John Key has made no secret of associating himself with the right-wing candidate for Mayor of Auckland, John Palino. I doubt that Palino has even a bolter's show against Len Brown, but someone has to give Len a challenge.
And what about the general election in 2014? Labour and the Greens would have been sharpening their policy pencils over Auckland rail as an issue that might have helped to divide Auckland voters and shift them a percentage point or two to the left.
So this incredibly lame 2020 flip-flop plan is designed to get that issue off the campaign agenda right now, before it's too late, and to steal some of Len Brown's thunder. After all, it was Len Brown who pushed the plan for an underground loop soon after he was elected Mayor, even in the face of the National government's refusals to help. The only way for National to neutralise and control this issue was to adopt it.
Poor old Gerry (from the South Island) was left to explain the dramatic U-turn, but I'm sure he took it all in good grace. Best to endure some ridicule now than face the oncoming train of Aucklanders' wrath in 2014.