Extension of electrification remains an option but ultimately a distant priority

Pressure from advocates for the use of renewable resources to complete electrification of the North Island Main Trunk line has grown as the price of oil has risen.

They look at the map of the North Island, and make the point that the sections of line not electrified look small, particularly as the electrified Auckland and Wellington metropolitan networks stretch southwards and northwards respectively.

Work done back in 2008 for rail infrastructure agency ONTRACK provides useful a perspective on this argument. It concluded that to justify electrification, a route should be all or most of the following: at or near capacity, densely trafficked, steeply graded, involve a long tunnel or be adjacent to an existing electrified route.

The routes to meet these criteria were Westfield-Te Rapa, Hamilton-Mt Maunganui and Otira-Arthur's Pass. The first two (in practical terms one, the Westfield-Mt Maunganui route) meet the density and adjacency criteria while Otira-Arthur's Pass meets the grade and tunnel test.

Given the density of traffic between Auckland and Mt Maunganui, the country’s busiest freight line, it would make no sense to electrify simply to Hamilton.

Another consideration is the incompatibility between the Wellington network extending as far north as Waikanae and the Trunk at Palmerston North.

The cost estimate at the time for the two most likely routes was in the vicinity of $900 million - undoubtedly more at today's prices. Obviously the lion's share would be taken by the Westfield-Mt Mauganui route.

The conclusion reached was that money on this scale could be spent on other projects which provided significant gains in transit time, capacity and reliability rather than on electrification.

An editorial on KiwiRail’s Express staff newsletter in March 2012 concluded: “As the NIMT electrification project itself demonstrated, we don't know what's around the corner. One of the reasons why it got the green light originally was the impact on the country of rising oil prices.

“There are plenty of analysts thirty years later who have predicted the end of peak oil. But for a rail industry that always has to make the best of a tight budget, today's realities are more urgent than tomorrow's possibilities.

“Extension of electrification should remain an option but ultimately it ranks as a distant priority.”