I think that the new structure will eventually carry all the cables, hoses, etc. to the tunnelling machine from a generator etc. located between Royal Oak Station and the tunnel mouth - not quite sure why it has to go over and around but there's presumably good reasons for it.
After checking out the tunnel progress I took a canal side walk, but this time decided to head west. The route here starts heading south-ish then curves round to the west parallel to Harrow Road, passing the end of Portobello Road and under Ladbroke Grove, then Kensall Green cemetery and crematorium. Off to the left behind walls etc. there are railway lines and an old disused gasworks
After 45 minutes or so the weather was starting to look pretty crappy so I found the next exit from the canal bank, which turned out to be Scrubs Lane - for the uninitiated, Scrubs Lane is not an idyllic country lane, it's a very busy road lined with scrap metal recycling depots and other fun industrial stuff. Not very pretty. I slogged uphill to Harrow Road, just beating the rain to a bus shelter, then caught a bus part way home, where I stopped to get some shopping and walked the last 3/4 mile or so back home. Total distance walked about 3.5 miles according to Google Maps - next time I really must remember to take a pedometer!
Finally, a few pictures I've been meaning to upload for the last couple of weeks:
Another picture of a bus on the bridge over the canal near Westbourne Park station, rather better than the one I previously posted - I have no idea who the guy on the bike is!
Another mandarin duck, one of three that were around on the canal last week, around the same place that I previously saw one.
Some interesting ironwork on one of the bridges passing through Regents Park
A swan I saw the same day
That's about it for now - hopefully I will eventually have some pictures of the first tunnelling machine vanishing etc., but it looks like it'll be a while before that happens.
nelc has found this animation of a tunnel boring machine which makes it clearer what's happening and what all the infrastructure is for