I went from London to Cardiff and back yesterday so I thought I would give an update, I could only saw the north side as it was pitch black on the way back!
The new Stockley Bridge to connect to the up slow lines at Airport Junction is complete with track, a connection to the up slow, OHLE installed and looks like it will be in use very soon.
So one new bridge nearly in use and nearby two very old ones to be demolished over the Christmas break at Thorney Lane, near Iver and Stoke Poges just west of Slough, these are the last to go as part of Crossrail bridge works in the western section.
So electrification progress, the section between the end of the new Reading train depot/Tilehurst and Didcot has about 80-85% pilling complete and about 25-30% of the masts have been installed with a very small proportion of these having a cross section bolted to the top but these are not portals.
Between Didcot and Swindon I would guess there is about 10-15% pilling installed and between Airport Junction and Reading about 5-10% of pilling completed, the Crossrail website still states that the completion date for electrification is Dec 2015, well they will have to go as fast as Lewis Hamilton to get finished in a year from now!, there are no masts on the above two sections as yet.
The furthest east pilling is just west of Iver and to the west is about 12 miles short of Swindon, however plenty of pilling installed at the new Filton Triangle Depot just west of Bristol Parkway.
On the signalling side nearly all the new locations have been installed from the Airport Junction to about 5-10 miles from Bristol Parkway. Plenty of new signals from just east of Swindon and then going west towards Bristol but none in the Swindon station area.
The Cardiff resignalling between Newport and Cardiff seems to have come to a grinding halt at present, new gantrys are up to just east of Cardiff Station, but there is still plenty of track work to be done before it becomes live which I believe is summer 2015.
I could not see any other new signals from Airport junction right through to just east of Swindon apart from the Reading station area.
So quite a bit done but they will have to get their skates on in the next few years to say the least.