I do wonder what the contingency plans are for a blockage on the CTRL, since currently Eurostars can divert via the old pre-CTRL route, but oviously once the 3rd rail capability is lost this won't be possible. Particularly problematic would be a blockage between the tunnel and Ashford, since unless they will be able to use the Shuttle terminal then they wouldn't be able to run through the tunnel. On the French side, TGVs and Eurostars can use the "classic" network if the LGVs are closed. I presume engineering work when required will be carried out with single line working and TSRs past the worksite. Another thing, is the AWS/TPWS being retained? I know St Pancras is going to have KVB which is the French equivalent, so there will be no need to use AWS under normal circumstances, but retaining this would be useful (removing it would prevent access to the platforms at Ashford for one thing, making Ebsfleet the first turnback point this side of the channel).