Trains calling at Wandsworth Common Platform 4 are exceedingly rare. The platform is locked out of service and only opened in the direst emergencies. DOO services are not normally to call there, and conductors (such as there are) must make sure the platform is unlocked if their train calls. Ironically, there are still DOO monitors, whereas Platform 2 has to make do with a mirror or manual dispatch!
Platform 3 is also rarely in use, but more likely to be - generally on the all-stations 0042 from Victoria, which sometimes calls at all the Down Fast platforms instead of the usual Down Slow ones. The step and gap is atrocious, as is dispatch visibility when a conductor has to work it (on Saturday -> Sunday nights). The same goes for the DF platform at Norbury.
I have seen that happen during engineering work albeit that was about 15 - 20 years ago - I actually traveled on one from platform 7 once. Pretty sure they used 8 as well at the same time.
GX have used all sorts of platforms at Victoria, but for commercial reasons (namely the fact that the Oyster/contactless readers on the barriers on 13/14 will charge more for Gatwick passengers than the ones on all the other Victoria platforms) it's far better for GTR's bank balance for the red trains to go into the red platforms!
During disruption, in particular, GX services will end up left, right and centre. The dedicated GX drivers don't sign half the diversions they used to, but I believe they can still use Platforms 7 & 8 as well as 9-19.
Platform 8 has had an interesting history from a route knowledge point of view - sometimes considered as part of the "Central" side of Victoria station for route learning purposes, and sometimes not. From a diagramming and signalling control point of view, it's really the latter. Platform 7 is definitely Victoria "Eastern" side.
(...an interesting little snippet, then: in Southern conductor route learning packs, which believe it or not still exist, I believe there is still a reminder that crews should familiarise themselves with the location of Victoria Platform 8. Apparently one poor soul once got a bit lost and tried hunting around the wall beside Platform 9 to get to 8, before giving up and cancelling a train...)
) to cross the Bradford Road junction without conflicts. The entry portal can be seen from trains crossing the viaduct if you look to the left-hand side in the direction of travel. The name is taken from Huddersfield's twin town of Unna in Nordrhein-Westfalen, not far from Dortmund. The French twin-town of Besançon gets the "Besançon Bridge and Loop" over the ring-road for traffic arriving in town from the A629 from Halifax and the M62. This can be seen beyond the sidings adjacent to platform 8.
