Most work so far is in the drawing offices and on surveys. The High Output plant contract was awrded a while ago.
No wires are up yet. They are altering bridges, for instance on the B&H east of Newbury.
Masts are already up as part of the new depot building project west of Reading station.
Reading station rebuild will include all the masts and portals for the OHLE. Concrete foundations for masts in the station area are going in now as advance works - just west of P10 for instance. They are not avoiding the Reading rebuild - it seems they are piggy backing on the existing work.
Latest key dates are that main construction begins Oct 2013
Construction complete and infrastructure available Sept 2016
Electric services to begin to Bristol, Newbury and Oxford Dec 2016
Cardiff is later, but not by much - maybe a year or so.
I'm assuming it is gantries in the station at Reading or are they going for more headspans?