The changes at SWR have shown that a 10-car railway is now unnecessary with the passenger loads now comfortably fitting in 8-car trains. Likewise, the coast routes no longer need 12-car operation and there are no longer 'peak extras' in the timetable. All of these things free up units to backfill the current 455 operation. They could look at running 5-377 vs 8-455 on some services, and possibly some routes can be cut where there is duplication - London Bridge to Caterham / Tattenham Corner trains running as shuttles to / from Purley would be one idea, Dorking / Horsham trains picking up stops north of Sutton again to eliminate the Victoria to Epsom service another, but there may well be others.
More routes running an hourly rather than half-hourly frequency through the day like East Grinstead will also create some slack in terms of maintenance schedules.
A number of these sort of 'soft' cuts could all add up to allow the 455s to go.
The trouble is, how long does all this continue to be true? The leading companies seem to be making the point that off-lease stock is quite likely to be promptly scrapped, so there’s a big risk we end up seriously short of trains to cater for a return in demand, which is quite likely to happen over time, especially inner-suburban.
Or, to put it another way, we could have undone a decade’s worth of capacity enhancement, and then be unable to afford to put that right.
It’s not like new fleets are settling down well, look at the 701s for an example of that.
The 379 solution seems to work as follows:
From
29x 387 + 19x 365 (*) + 18x 313 = 66
to:
29x 387 + 30x 379 = 59
If one adds the 6x LTS 387s or a few 387/2s then this is essentially the same as was started with, and in fact amounts to *more* vehicles as the 313s are 3-car. I can’t see the 455s fitting into this, not without a very considerable thinning of services and lengths.
(I’ve taken the 365 figure to be 19, as although GTR had 21 two of these seemed to be “over & above”).