So below is an outline diagram of the lines in the area including my modifications to history. This should help plan goods and passenger traffic, which in turn will affect the design of Grogley Junction's track plan. I will probably need to add distances and finally decided station locations on the extension to Mawgan Porth to create a new timetable.
The lines in red indicate my alterations/additions to history
The building of the line from Ruthernbridge to join the Newquay line reduces the number of reversals required to transport clay from Wenfordbridge to Fowey. It would also take this traffic away from the GWR man line.
The inclusion of two stations on the Mawgan Porth extension are only speculation at the moment. Thought St Columb Major was mentioned in a proposed Wadebridge to Truro line.