May's pylon is a little late arriving, but I hope that the wait will have been worthwhile. In the finest traditions of Pylon of the Month, it was a picture I took myself from the window of a moving car (before all you road safety conscious pylon fans get in touch, don't worry; I was in the passenger seat) as we drove over the Avonmouth bridge on the M5 near Bristol. In fact on the Wikipedia page about the bridge you can just about see the same pylon. What caught my eye was the height of the pylon and the fact that it is considerably taller than the previous one in the chain. Presumably the power lines need to be taken higher to cross the River Avon rather like the ones used for the Tees crossing which are the tallest in the country at 145m (dedicated fans will of course know that Pylon of the Month has mentioned the Tees crossing back in February 2013). Mark Brennan, the project manager had this to say about the Tees crossing:
“.....We need to build very tall towers to support the wires because of the width of the River Tees at the crossing point and the fact that we need to make sure there is a safe clearance distance for the ships which will pass under the line.”
I imagine that the same is true for the Avon when it comes to the length of the span but perhaps not the shipping. Anyway, if you look carefully at the image above you will see the wires sloping up steeply to the top of the pylon from the right hand side.
Just by way of information and because it is one of the most random Wikipedia pages I have found, the longest span in the UK is the Aust Severn Powerline crossing at 1,618m. If that isn't enough for you, how about a page listing spans from all over the world and the heights of the pylons that support them. It seems that the tallest pylons in the world at a whopping 370m are in China linking Zhousan Island to the Chinese mainland.
Finally this month, it looks as if my request back in Febraury 2013 for a stockbridge damper might have borne fruit. I've got my fingers crossed and I also now know even more about aeolian vibration and pylon lines as a result of my contact. I'll be writing more about this subject soon so tune in again next month to see what happens next. In the meantime, please do watch this fantastic 30 minute documentary, 'Silvering Up'. It follows a team of four pylon painters and the speed at which they work and their complete lack of fear as they clamber over pylons (without safety harnesses) is a real eye opener.