You need to look for a closure in the Basingstoke station area, because if the West of England line is available then XC▸ would be able to reach Southampton via Andover and Romsey as it’s quicker.
Paul
The Guildford diversion was in use today, but yesterday the Andover route was in use. That's from ther EAS:
SWR» : ON FRIDAY NIGHT, 1B01 TO TERMINATE AT
BASINGSTOKE. WEYMOUTH SERVICES TO
DIVERT VIA GUILDFORD AND HAVANT ALL
WEEKEND. ON SATURDAY, A SHUTTLE SERVICE
WILL OPERATE BETWEEN SOUTHAMPTON AND
PORTSMOUTH TO WINCHESTER. RAIL
REPLACEMENT ROAD SERVICES TO OPERATE
BETWEEN SOUTHAMPTON
CENTRAL/WINCHESTER AND BASINGSTOKE.
XC: ON SATURDAY, BOURNEMOUTH SERVICES
TO DIVERT VIA ANDOVER & ROMSEY AND
REVERSE AT SOUTHAMPTON CENTRAL.
NEWCASTLE SERVICES TO START AND
TERMINATE AT READING. ON SUNDAY,
BOURNEMOUTH SERVICES TO DIVERT VIA
GUILDFORD & HAVANT. ECS▸ TO DIVERT VIA
JUBILEE SIDINGS. SHUNTER TO BE PROVIDED.
GWR▸ : ON SUNDAY, 5O81 TO BE DIVERTED VIA
NETLEY & SOUTHAMPTON CENTRAL
DB» CARGO: ON SATURDAY, EASTERN AND
WESTERN DOCKS TRAFFIC TO DIVERT VIA
ANDOVER & ROMSEY. ON SUNDAY, 6M38 & 6O38
TO DIVERT VIA GUILDFORD AND HAVANT.
GBRf: ON SATURDAY, WESTERN DOCKS TRAFFIC
TO DIVERT VIA ANDOVER & ROMSEY. ON
SUNDAY, 4Y19 AND 4Y81 WILL NOT RUN.
FREIGHTLINER: ON SATURDAY, ALL TRAFFIC TO
DIVERT VIA SOUTHAMPTON, EASTLEIGH,
ROMSEY & ANDOVER.
And that's an up-to-date one. In the past the EAS was complicated to download as a huge zip file, the only alternative being a PDF relying on automation features that never worked for me. But now there's a PDF per route per year. You still need to know what you are looking for (as well as how to read the tables in the file) of course:
This is the "Operational Rules" page on the NR» web site.Look down the page and click on "EAS 2021" (or "EAS 2022" for next year)
Choose V4 (I think it's just more recent that V2 ... but who knows?)
The file names start with a short version of the route name - WR for Western, WX for Wessex - and you want the one that ends with "V7" (the big one).
Note that, strictly speaking, the EAS is a draft for discussion not the final plan That's why it has "Superseded by CPPP" stamped across it - that being the "Confirmed Period Possession Plan". In theory that's frozen 26 weeks in advance, but the current Wessex one was last edited on Wednesday.