Each nation plans its network; the spines join them.
New Zealand’s corridors follow the North Island Main Trunk and the South Island Main North and South lines.
Routes are indicative. Corridors are drawn city to city, through the cities on the existing railway wherever a line exists: MMC corridors follow those lines, upgrading the line or running above it on viaduct. Where no line exists, the corridor is new build. Final alignments are set at detailed design by terrain survey, geotechnical analysis, environmental and cultural heritage assessment, and agreement between the nations they connect.
| Nation | Corridors | Straight-line km | Built km (×1.2) |
|---|---|---|---|
| New Zealand | 3 | 1,200 | 1,400 |
| Papua New Guinea | 1 | 300 | 400 |
| Oceania | 4 | 1,500 | 1,800 |
Cross-border links are counted separately. Built km = straight-line km × 1.2 (stated assumption).
Australia is shown in detail on the Australia page and in the MMA plan. Papua New Guinea: Port Moresby – Lae. The undersea links are shown on the World Network page.