The standard gauge line followed a new alignment through the Avon Valley of the Darling Scarp east of Perth. This was the first section of the new line to be constructed, tracks on this section being and dual gauge. For a short time before its demise, The Westland was routed via the new Avon Valley line, and the original ascent of the Darling Scarp via the Swan View Tunnel and Chidlow was closed.