This line was envisaged as becoming the Main North Line to Nelson and Blenheim, but instead, a coastal route via Parnassus and Kaikōura was chosen. The line through Medbury had its furthest terminus in Waiau and it became known as the Waiau Branch.
Initially planned to run from Nelson and Blenheim, this line took a coastal route via Parnassus and Kaikōura instead.  The line through Medbury reached its farthest point at Waiau, becoming known as the Waiau Branch.