The high speed railway line has been announced.

Petition number 10 here:

 http://petitions.number10.gov.uk/railhighspeed/

sign it and confirm the email they send.

here are the PDFs of the Route:

Wendover section

Great Missenden section

Amersham section

Chalfont St Giles section

The whole thing (6 MB PDF)

The Government says the route, which follows the A413 corridor, 'appears best to meet the Government’s objectives for optimising journey times and cost, and for managing impacts on the local environment and communities in an acceptable way. '
The other two routes are 'significantly inferior'.  This route would run in tunnel from a rebuilt Euston Station, surfacing in West London to follow the route of the existing Chiltern Line, leaving London near Ruislip. 'The route would proceed largely in tunnel from the M25 as far as Amersham, and then continue above ground to the west of Wendover and Aylesbury, partly in tunnel and partly following the existing A413 and Chiltern Line corridor.

all maps are here: http://www.dft.gov.uk/pgr/rail/pi/highspeedrail/hs2ltd/route