(04 Feb 2015, 8:24 pm)Dan wrote Can't help but feel it would make the costs of running the X21/X22 go through the roof.
The advantage of double deckers is that they provide the extra capacity when it's needed; instead of having more peak time runs to combat full buses at this time, double deckers only require the one bus (and hence driver) and lowers costs. The advantage of light-weight double deckers is that it allows for savings on fuel.
Exactly
Also notice that there's an extra peak time journey on the X20 using a bus off the 35A.
All that's maybe needed looking at is something similar to how its worked at Stockton depot - our 27/27a operate a 7/8 minutes flow one way at peaktime and 15 minutes flow in the other (ie from 1530 onwards, it's a 7/8 minutes flow to Netherfields but every 15 back in) with buses dropping off to work peak time services (1 27 drops off to work the 1710 X5 while the rest end up on the 17 group at some stage).