(15 Sep 2020, 6:12 pm)tcts24 wrote There's probably rarely any real logic to choosing route numbers. There are still a few 1XX services in the Wear Valley, 2xx routes in East Durham and 7xx numbered routes around Chester.
I've been fascinated by route numbers for years. I particularly dislike things such as those mentioned by somebody else 1/1A/1B and X1, 5 and X5 etc being confusing. If the 1 had a express introduced that would be the 1X, which is stupid! I agreed with Coaster 1/2 becoming 1/1A as it frees up more numbers.
Suppose with a limited amount of numbers, it can't be avoided. Branding does help, like Coaster 1 and Red Arrows X1, or now all expresses will be X-lines so will be totally separate.