well in fact , this isn’t that much easier to understand , so i’ve just change the first representation is this the correct path of each line ? :
do you have a 6 track section going from the “Hub” to the yellow / pink terminus (woodley) ? (I hope not )
if the red line make a stop at the Hub (St Ives) i think the best solution is to remove the pink AND the yellow line , ppl will use the red line to reach the HUB then the blue line to Shaffesbury
unless Woodley isn’t the terminus for those two line ?
if there is more city bellow shatfestbury , make a third loop using the pink line , add St Ives in the path (to reach the HUB) and remove the yellow line