 In 1954, it re-joined the western line south of Manor Park and superseded the old route.On 1 March 1954 the former Hutt Valley Branch became part of the Wairarapa Line and the western route was truncated into the Melling Branch from Petone.The deviation included a new bridge across the Hutt River, replacing a section of line now used by Silver Stream Railway

The Rimutaka Incline was difficult, costly and time-consuming to operate, but as the Wairarapa Line had become a secondary route since the acquisition of the Wellington and Manawatu Railway in 1908, its replacement was not a priority.