I'm slightly surprised there isn't a discussion about this already, but between the dates of the 29th of August and 1st of September, it would appear that Southeastern will be borrowing Waterloo Mainline as a diversionary terminus whilst the London Bridge blockade is underway.
I originally assumed this was some kind of error, but I've had several people confirm this now, and
publicity appears to have been updated to quietly include this information.
It looks like someone in the planning department has remembered that the Waterloo curve off of the Chatham line actually still exists. What I'm not currently sure about is: Which services will actually serve Waterloo? North Kent services will likely continue to use Cannon Street and/or Blackfriars, but as Victoria probably cannot take all the slack like it normally does during engineering weekends, I would imagine that it would be down to the Hastings services, and the Dover services.
This is just guesswork - the timetables aren't likely to be published until June, and I don't know what kind of driver training or familiarisation is going on in the background in preparation.
Whether this is just a once-in-a-lifetime change, or a potential trial run of future engineering/disruption contingencies, I'm sure a few spotters would like to get down there when this is happening.
