On 09/10/2014 18:30, Steve Fitzgerald wrote:
[...]
I thought that TfL had considered walk-through for the 2009 stock on
the Victoria line, but rejected it as impractical.

AIUI, this proposed new stock is not intended to replace the 2009 stock.

I believe it was not TfL as such but Metronet (as was) who as the agency
charged with this upgrade decided it was too risky so they took the safe
approach to archive the target.


That was my understanding - less risky to go with the proven design.