[1] It flows west from the slopes of Mount Ruapehu, and from the Hauhungatahi Wilderness Area,[2] before entering rough hill country, veering southwest and entering a gorge cut almost 100 m (330 ft) into the volcanic rocks.

[4] The main trees logged were rimu, mataī, kahikatea, tōtara and miro.

[6] A proposal to create a track to Te Kohatu waterfall was rejected as being inappropriate for a wilderness area.

[9] SH4 (originally built by the railway for access to its construction sites)[4] crosses on a much lower bridge near the viaduct.

[10] Just to the north of the viaduct, the Makatote Tramway has a Category 2 listing by the New Zealand Historic Places Trust, with remnants of rails, skid sites, a log hauler, water pits and bogie wheels.