Are those numbers correct?
By my reckoning:
455s - 91 units, 364 vehicles
456s - 24 units, 48 vehicles
458s - 36 units, 180 vehicles
707s - 30 units, 150 vehicles
which gives 181 units,
742 vehicles
Which will become
30x5 car (150 vehicles)
60x10 car (600 vehicles), so
750 vehicles
with the 442s as well (18x5 car) that gives
840 vehicles, so a net gain of
at least 98 vehicles, and I don't think anything has been said about the 458s going other than in the BBC report - this part of the strategy is the main thing that needs clarifying in my mind, i.e. will Reading be worked by the new suburban stock, a cascade from the Portsmouth line as a result of the 442s, or the 458s as per the original Stagecoach plan etc.
EDIT - the ''Windsor Lines'' (including Reading) are included in those routes which are getting the new trains on the
DfT map, what isn't clear is whether or not they will run to Reading, and the
First/MTR infographic only talks about the (already known) increase in services to 4tph.