(07 Apr 2021, 6:44 pm)mb134 wrote The X20, at one point (2011ish if memory serves), served Newbiggin then Ashington then Newcastle via North Seaton. It was scrapped because there was no demand and subsequently terminated at Ashington (before the Alnwick extension)That was because the X21 was also running every 20 minutes and back then, it ran a quicker route missing Nedderton. So that (although it was still a good 10-15 mins more than the X20) plus the fact that the X20 was likely unreliable due to tight timings would've made the X21 a no brainer.
GNE had the same issue in Derwentside so to boost passenger numbers on the X70/X71 and also the X30/X31, journeys were cut from the frequent 43/44 right through to what the 6/6A are now over the years.