Note that the Crossrail extension is dependent on Crossrail's assent and will be completed after the main Crossrail construction phase
http://windsorlink.co.uk/LocalMap.aspx
Datchet
New bridge[s] to replace existing level crossings, solving traffic problems. Impact of bridge minimised by dropping level of train track and station by 6’. New connections to the north (via Windsor and Maidenhead), Heathrow (direct) and the south (via Staines and Ascot).
http://windsorlink.co.uk/MyTown.aspx
External link to Windsor Lines Passenger Association http://web.ukonline.co.uk/alan.marlow/wlpa1.html