(06 Dec 2017, 9:07 pm)JP6004 wrote Hmmmm before xmas? Yes being that young seems odd to just have them as spare. Saying that might be used to make up PVR on CC and a few spares for washy and dptford with the view to have cascades displace presidents
If that's the Cobalt Clipper, then excluding the Formica bridge replacement, the PVR for the 309/310 is 16 vehicles (used to be 15 but got increased in Sept 2014 when the 309 frequency was increased between W.Bay and Blyth) with either 6116/17 acting as spare depending on which one makes up the PVR.
Any extra B9s would act as an additional spare taking the spare vehicle ratio back up to 2 spare for every 8 which would be enough with either a PVR of 16 or 17, the latter being a possibility depending upon the timings of the 310 once Norham Road bridge is completed.
Speaking of the devil, if the 309 / 310 ever went standalone, it would give GNE a good fallback for the Castles Express Streetdecks if they show signs of trouble (let's hope that they don't).