(10 hours ago)L469 YVK wrote To be honest, other than maybe the Blyth > Cramlington section of the X8 or some handy little tweaks / refinements, I wouldn't mess around too much with any of the Northumberland network. It's pretty straightforward and to a large extent does the job passengers need it to do, it's fairly simple and makes money.
It's in a much better state than the mess in similar type areas with a myriad of routes going on whatever mystery tour and one going one way with the other going a different despite having the same route number groupings - an example being the X70/X71/X72/X73.
I agree with that. They need to be vigilant about how the train line might change travel patterns, but at the moment it seems to be a fairly solid network.