I really suggest, you put this Website into your favourites, This is the site run by Matt Cross and a few other people which also runs Rideas.co.uk
Anyway, the address is
http://www.sw5.rideas.co.uk/ Basiclly, its contains all the latest info reguarding SW5 and has upto Date Construction pics, Infact there are even some there from yesterday(19th June) Check them out, at the moment, footers and work are happening for the second tunnel, and steel work is happening for ths station. At this point in time, track is predicted to arrive about August time. NOTE - Track could arrive sooner, or even later, its only a predicted guess