(24 Jul 2016, 8:34 pm)R852 PRG wrote I think tampering with the 21s would be best avoided. We've had a system of 21/21A/21B/22 and so on in years gone by. The 21 did Newcastle-Chester-le-Street, 21A to Houghton-le-Spring and 21B to Witton Gilbert, 15 minute frequency I believe, with two terminating at Chester every hour and one 21A/21B hourly. Combing the 21 and 34s may seem cost effective, but I think it's easier to have them separate. 21 is regarded as the flagship route at Go North East, while the 34/34A are just a local service with a significantly lower PVR.
Your suggestion for the X21 would defeat the point of it being an express to Newcastle from Chester-le-Street. Including the Metrocentre would probably increase the journey time from 30 minutes to about 45 at the least I'd expect. Both the X21 and X22 can receive heavy loadings on their own on Saturdays, especially mornings and evenings, and combining the two would either push people onto the X24 for the Metrocentre (inconvenient to the majority, as a lot of school students use the X22 and use solely Go North East, with the appropriate bus passes, but both the X22 and X24 get a similar number of OAPs) or result in people being left behind.
As for the X50 idea, I don't think there is as much demand for a 15-minute ''fast'' frequency between Durham and Chester, but mainly the latter and Newcastle. The 21s to Durham used to operate every 10 minutes until late 2012 when service revisions coincided with the arrival of the Hybrids, and I can vaguely remember the X21 being increased to every 30 minutes while the 21 went to a lower frequency of every 15 minutes. Might be wrong, but that's my recollection of things.
I can understand your logic with wanting to combine the likes of the 34 and 50, which in itself I think is a good idea and might be more plausible than combining the 21 and 34s, but in terms of fast services, I think Newcastle needs to be focused on more than Durham.
Each operated on a 30 min frequency for the majority of their existence, with the likes of the 724 supplementing the service along Durham Road and extending to Bishop.