Fantasy: How would you have built HS1?

[Sad Sprinter]

I’ve recently become fascinated with BR’s original proposal for he Channel Tunnel Rail Link, that would have involves a large carver underneath Kings Cross used for Thameslink and Eurostar trains connected to a long tunnel out towards Foots Cray. Here is an excellent illustration of how the “Kings Cross Low Level” station could have looked:
https://www.flickr.com/photos/iqbalaalam/8316011256/in/photostream

So it got me thinking, how would you have built HS1?

I would have built the line alongside the Tonbridge to Ashford Line, then alongside the main Sevenoaks to Tonbridge Road and Tunnel under the North Downs to Westerham, then run the line towards Shirley in Croydon and Tunnel under South London to Nine Elms where it would terminate at Waterloo. I always thought Waterloo was a great terminal for the Eurostar and think it should have been kept as such instead of moving it to Kings Cross.

 

[Indigo Soup]

The Kings Cross/St Pancras area has a lot going for it as an HS1 terminus, and the original proposal would have lent itself to Kings Cross Low Level being configured for through running to the East Coast and West Coast main lines.

I'd have fairly closely followed British Rail's preferred route, myself - more or less as built up to the Medway, bridging it on a more westerly alignment to tunnel between Cuxton and Cobham (more or less) before following the Chatham Main Line and Catford Loop, going into tunnel around Hither Green to run direct to Kings' Cross.

 

[Peter Mugridge]

I'd have run it to Bricklayer's Arms with the entrance and exit at the north end and connected with London Bridge ( i.e. international facilities between London Bridge and the north end of Bricklayer's Arms ) but at a low level and with provision for a tunnel connection to both the WCML and ECML for future through running.

This does of course mean it would need a long approach tunnel run underneath the existing line, but that's exactly what they have done between Dagenham and St Pancras anyway... the only difference is that the new alignment would have run west of Ashford rather than east of it and would have pretty much run straight to the Orpington area and started the approach tunnel around there.