Thanks. Why a two month break between further new diagrams? Seems a bit extreme…..
As well as Christmas getting in the way if adding two further diagrams that will usually need twice as much training. It looks difficult on paper to increase one diagram at a time after the next two on the current routes. All of the below is from looking at the schedules and programmatically combining them based on associations/platform allocations so is educated guess work.
For an additional Windsor there's a diagram starting and ending at Feltham Depot, the other two Windsors then swap between Staines CHS and Windsor itself which even if could switch to Feltham Depot instead of Staines CHS would be awkward.
At the timetable change the Shepperton currently run by 458/5s changes to start and finish at Strawberry Hill CSD. If it does that could be 701 operated and drop the number of 458/5 diagrams which presumably will be required soon anyway after the final 458/5 goes for conversion leaving just the extras.
After that there would be a pair of Sheppertons which with some tweaking switch between Strawberry Hill CSD and Wimbledon Park which could go over as pair. The diagram is different on Fridays and at that point it will get increasingly difficult to avoid running 701s at weekends.
With the stakeholder launch event next week there'll be a high expectation that roll-out is going to ramp up significantly. If it's as glacial as suggested here then there's going to be a bit of comeback.
Surely the point of stakeholder engagement is to get ahead of the narrative and set expectations you can meet. Not all stakeholders will be aware of current progress and providing certainty is often appreciated even if the timelines are longer than ideal.