The HS2 report of November 2015 gave sound reasons why direct high-speed trains from the North to major European cities made little economic or operational sense.
There is no point in duplicating Eurostar’s services to an increasing number of European destinations. Trains carrying both commuters and passengers who have passed through Customs and Immigration would be impracticable. However, there is an excellent case for services requiring a single convenient change - this only needs an HS2-HS1 rail link. With such a link in place, a range of options is available:
1. HS2 trains timetabled to meet departing and arriving Eurostar trains would terminate at St Pancras instead of Euston.
2. HS2 trains utilising HS1 could provide services to Stratford for Docklands, and Ebbsfleet International to connect with Eurostar and Javelin trains into Kent.
3. The provisions of a further tunnelled link between HS2 Old Oak Common station and a portal at Acton sidings would allow Great Western Main Line services to use the HS2HS1 link through to Ebbsfleet. The HS2 section between OOC and Birmingham limits the number of trains per hour between the North and London because of the long stopping distance from speeds of 360kph (224mph). The section between OOC and Euston, with a maximum speed of 230kph (143mph), offers significantly higher capacity.
A technical note HS2-HS1 Link; the Solution was sent to HS2 in April 2016. The solution comprises twin shafts in the railway land south of Adelaide Road, to facilitate the construction of bifurcation chambers similar to those on Crossrail at Stepney.
These chambers would be linked to an exit portal between the North London Line and Barker Drive by twin tunnels passing under the Northern Line and Fleet sewer and relief tunnel.
The estimated cost using HS2 rates is £300 million to £350m. The provisions of a connection from Old Oak Common to Acton sidings and improved signalling on HS1 to Ebbsfleet would bring the total cost to £1 billion - a very small price to pay for a highspeed route across London.