Walbran Transport Analysis

« Other projects

Paekakariki to Pukerua Bay Dual Tracking

The North Island Main Trunk line between Paraparaumu and Wellington is dual tracked except for the section between Pukerua Bay and Paekakariki.  While this single tracked section is not a major constraint on commuter rail operations at present it will become so in the foreseeable future.

Wellington Regional Council commissioned Warwick Walbran Consulting Limited to provide a construction cost estimate for the dual tracking.  The estimate produced included both an expected estimate and a 95 percentile estimate.

There was a large difference between the expected and 95 percentile estimates, reflecting the number of large risks associated with the project and the early stage of project development.  The difference between the expected estimate and the 95 percentile estimate is expected to decrease as investigation and design advances.

Major cost risks are the extent of earthworks and ground stabilisation that may be required as a consequence of the unstable (or barely stable) nature of significant areas of the escarpment; and the unknown risks.

Large (2 million cubic metres plus) quantities of cut to waste will be generated.  There may be an opportunity to make good use of this as fill to extend State Highway 1 seaward.  However at that stage there had been no decision to do so and it was thought that the resource consent issues would be substantial.

Large amounts were allowed in the Funding Risk for the uncertainties associated with earthworks volumes, cut stabilisation treatment and for an additional electricity substation.

« Other projects