The article doesn't explain, but one of the incoming ideas is discontinuous electrification. In fact at the
WWRUG» committee meeting last night, we were looking at the future of rolling stock for Cardiff <-> Portsmouth and wondered if charging ramps at major stops, based on there Wealing experiment, might be a future? Three minutes at each of Bristol Temple Meads (where the train reverses anyway), Westbury and Salisbury, perhaps?
Make a benefit out of the feature at Salisbury. Imagine ...
1. the train from Portsmouth arrives and puts its shoe down
2. the train from Waterloo to Exeter arrives and departs
3. the train onward to Cardiff lifts its shoe and carries on.
And I can imaging at Westbury a similar setup with the hourly Cardiff - Portsmouth and the hourly Oxford - Weymouth making 2 way connections.