Crossing the Southern Alps via mountain passes, tunnels and viaducts, this single-track line links the east and west coasts of the South Island.

One of the success stories of the privately owned rail system in New Zealand has been the promotion of the train from Christchurch, through the Southern Alps, to the west-coast town of Greymouth. The TranzAlpine Express has become a popular tourist service, as a one-way link between the coasts, and as a round-trip excursion from Christchurch. The narrow-gauge train is diesel-hauled and the carriages have large picture windows; there is also a carriage with open sides for viewing and photography. Departing daily from Christchurch in the morning, the train crosses the neat and tidy farmlands of the Canterbury Plains, passing through a number of small towns before stopping at Springfield. From here the journey is spectacular as the train continues across viaducts and through tunnels across the Canterbury foothills up to Arthur's Pass. At 737m, this is the highest railroad station in the South Island and sees the arrival of many visitors bound for Arthur's Pass National Park, which offers numerous opportunities for hiking and mountaineering. Shortly after leaving here the train enters the 8km Otira Tunnel for the descent of 259m to Otira. Now on the other side of the Alps, the rainforests and scrubby landscapes of Westland offer a contrast in scenery to the eastern side. The line continues past mountains and along river valleys before running alongside the Grey River into Greymouth. The train returns to Christchurch in the afternoon.