I didn't express myself very clearly. The Victoria Line is already chronically overloaded so why would you extend it?
Well I did, so I have no idea why I am needing to say the same thing for the third time.
The suggestion by the TfL representative about extending the Victoria line is for post-Crossrail 2 when it will release capacity to allow it to happen.
No one is suggesting extending the Victoria line before CR2 opens.
No one is even suggesting any extension is even planned until CR2 is approved and budgeted, so there is a confirmed intention to release that capacity.
I am suggesting that once the CR2 route is approved and does not come via Streatham that people will then campaign for an extension to be constructed following the opening of CR2.
The people who argued about the Wimbledon loop have, of course, shot themselves in the foot. By going on and on about the trains running north of Blackfriars they've wrecked the Thameslink planning assumptions and deprived themselves of a doubled train service. If the Wimbleloop trains had terminated at Blackfriars the trains would have been increased to x15 mins but now have to remain at half hourly in order to fit into the service pattern.
That is complete nonsense.
Not only has there never been any proposed increased frequency, it was explicitly ruled out because of the capacity constraints at Herne Hill where the Victoria - Bromley South line crosses on flat junctions. It was said that to allow an increased frequency would require grade separation, which is difficult on such a constrained site. This is also what prevents platform lengths being extended beyond eight carriages.
The 2011 London and South East Route Utilization Strategy, which officially recommended the post-2018 Thameslink routes, only included the current 2tph service each way from the loop into the bay platforms. But it also proposed a 2tph service to Kent House and a peak 2tph service to Medway. So the bay platforms would have been at capacity as they can only accommodate 8tph so making any increase impossible under them
And those "planning assumptions" were purely based on resilience, not capacity. With a 16tph split of Thameslink services via London Bridge and only two bay platforms only a peak of 16tph can enter Blackfriars via Elephant and Castle. With four tracks from Loughborough Junction this approach will remain significantly under used even after the project completes. The West Anglia line has a peak of 22tph into Liverpool Street on only a two track approach from Bethnal Green.
But if it the Herne Hill approach were not a problem and the bays available then there is nothing preventing a combination of terminating services in addition to the cross-London ones to increase the loop frequency.
It is also worth remembering the 2008 South London RUS recommended that the terminating capacity freed at London Bridge could be used to run a half hourly service around the Sutton loop instead. This would avoids Herne Hill yet still allow a 15-minute service on the loop, and with a same platform change at Streatham gives a choice of both London Bridge and Thameslink destinations.
Although no RUS has addressed the biggest constraint to a 15-minute loop service, which is the single track section through Wimbledon station which would need to support a bi-directional 8tph service. Which it could do, it already reaches 7tph in the morning peak, but means it has little ability to recover in the event of problems.
Hundreds of millions are being spent to connect those tracks into the Thameslink route east of London Bridge but the Wimbleloop decision means there are no paths via Blackfriars for those trains.
You are clearly just making stuff up now.
The Darford proposal had already been explicitly dropped by the South London RUS published in 2008. The reasons given were it would require too many conflicting movements on the line and that a 20-minute service pattern works better on it so it would not fit in with the 15-minute Thameslink patterns. Although as Thameslink stock will be in a mixture of 8 and 12-carriage stock they would be restricted to 8-carriage rather than 10-carriage ones services without a rebuild of Dartford station, which no one was proposing.
The Dartford services would also have used the London Bridge approach, so was completely unrelated to the issue of how the Elephant & Castle approaches are used. The are practically segregated from each other.
It was subsequently also not in the service summary in the 2011 London and South East RUS, which was what officially suggested that Catford line services run through Thameslink and Sutton loop ones terminate.
The consultation on which services should run through Thameslink was not until 2012, and the decision not made until 2013, so at least five years after the Dartford had already been officially dropped from plans.
I am also not sure how you think millions were spent connecting tracks to the approach to London Bridge when that is where they were already connected. The junctions are being greatly remodelled to allow grade separated filtering of the Cannon Street, Thameslimk, and Charing Cross lines on approach to London Bridge. That new layout has no specific connection between the Thameslink and north Kent lines, and if anything would probably reduce capacity on the north Kent ones if they did because of the conflicting movements required for down services.