A pylon hunting walk I did near Tunbridge Wells

[danny1962]

I like to go out walking in the fresh country air, and I sometimes combine a walk with an opportunity to go pylon hunting.

Here's a nice one I did a few Sundays ago. I parked in the Village Hall car park in Five Oak Green (near Tonbridge in Kent) and set off towards the Pembury Substation a couple of miles to the south west. I was particularly interested in seeing the multi-way split pylon shown at TQ637434 and I wanted to see if I could ID the routes heading to the north and to the west of the split.

I take photos while I am out, partly for reference, and partly so I can submit any decent ones to Geograph (a photo sharing site where pictures of the local environment are catalogued against OS grid references).

I often wear an ex-army jacket on these walks, it's excellent for this purpose. There are plenty of big pockets to store maps, mobile phone, camera, binoculars etc. It has a rip-proof mesh sewn into the fabric so it's perfect for going through the undergrowth without getting torn. Sometimes I might venture off track a little in order to get a better view or a better photo, so strong army boots and an indestructible jacket can come in handy.

So the path took me through a hop field, where a worker was fitting strings to the wires and poles. It looked a skilled job. Photo here: www.geograph.org.uk/photo/3918800 . I'd never seen this being done before.

I passed the Pembury Substation www.geograph.org.uk/photo/3920137 and I went onwards to find the multi-way split. Going by what I could see, rather than what the map said, I headed across boggy ground to the split. This was clearly not where the OS map said it was. Here it is... www.geograph.org.uk/photo/3918557

The route code here is PW, which I believe starts at a substation near Gravesend, heads south then takes a sharp right turn here and heads westwards towards Crawley, with a connection to the Pembury substation at the sharp bend. The PW route mainly uses 3-arm towers, not 6-arm ones... photos here www.geograph.org.uk/photo/3319702 and www.geograph.org.uk/photo/3321136   I'm not sure what the use of 3-arm towers implies about the route.

The pylons must have been restrung at some point in the last 2 years, since an older photo on Geograph shows the same pylon (PW82) as being a deviation pylon without the 3 way split www.geograph.org.uk/photo/2850628 .

Here's the photo of the original 3 way split location as shown by the OS map
www.geograph.org.uk/photo/3941265 ... as you can see, it is now only a 2-way. The ground here is very boggy and I wonder if continual access difficulties for maintenance workers was behind the decision to alter the location of the split.

This route is PBA, which runs east from the High Brooms substation, past Pembury and onwards to connect with the north-south PCA line near Marden. The preceding pylon on this line (PBA21) has an unusual feature in that the insulators do not hang vertically, instead they are offset and appear to be straining to one side. I'm not sure what's going on there... www.geograph.org.uk/photo/3941933

On the way back I switched on MyTracks on my smartphone so I could get a track of my route. There's a kmz file and a route map here: docs.google.com/file/d/0BxVAEmkNA8xQYWtsdG8xWGpJT1U/edit

I didn't manage to do all the research on one walk so I came back again to pylon spot from a different direction. It's good exercise and it's a good way to explore the great outdoors. Have a click on my Geograph profile and you'll see some other photos I took around the area.

If anyone can shed more light on some of the points I raised here I'd be interested to know.

[yv47r]

It is nice to combine a nice walk with some pylon spotting to try and track down certain towers or places on the maps. I must try and do some more fieldtrips soon!

Cheers Paul

[rillington]

Apr 26, 2014 16:34:35 GMT -5 danny1962 said:

This route is PBA, which runs east from the High Brooms substation, past Pembury and onwards to connect with the north-south PCA line near Marden. The preceding pylon on this line (PBA21) has an unusual feature in that the insulators do not hang vertically, instead they are offset and appear to be straining to one side. I'm not sure what's going on there... www.geograph.org.uk/photo/3941933

I didn't manage to do all the research on one walk so I came back again to pylon spot from a different direction. It's good exercise and it's a good way to explore the great outdoors. Have a click on my Geograph profile and you'll see some other photos I took around the area.

If anyone can shed more light on some of the points I raised here I'd be interested to know.

Many thanks for posting the pictures.

Regarding the offset insulators, there's an example of this in north Manchester where a PL1B suspension tower has offset insulators. It's easily visible from the M60 and if I am correct, close to the M60's junction with the M61.

[naughtyhorse]

Hi Danny,

"The PW route mainly uses 3-arm towers, not 6-arm ones... photos here www.geograph.org.uk/photo/3319702 and www.geograph.org.uk/photo/3321136 I'm not sure what the use of 3-arm towers implies about the route."

the 3 arm towers denote a single circuit line. electricity is transmitted/distributed using 3 phases (it is electrically efficient) so what you would see as the 2 wires (excluding earth) in your house is actually 1 phase and the neutral(earth, sort of). different houses on your street will be connected to different phases. most steel towers carry 2 circuits plus an earthwire - so seven wires. some carry just the one circuit (mostly 132kv or 33kv) so 3 phase wires and 1 earth wire.

more on 3 phase here
en.wikipedia.org/wiki/Three-phase_electric_power


"This route is PBA, which runs east from the High Brooms substation, past Pembury and onwards to connect with the north-south PCA line near Marden. The preceding pylon on this line (PBA21) has an unusual feature in that the insulators do not hang vertically, instead they are offset and appear to be straining to one side. I'm not sure what's going on there... www.geograph.org.uk/photo/3941933"

What's going on there is they built the tower in the wrong place! strictly speaking a suspension tower (one where the insulators hang vertically) can take an angle of deviation of 2 degrees - but the insulators swing over to one site and look a bit daft.

Having dodgy ground is not normally god enough reason to relocate towers - no matter how bad ground conditions might be by making the foundations deep enough and numerous enough a stable base can be established - towers at river crossings are often build slightly out from the river bank on artificial islands for example.

thanks for the post

[danny1962]

Apr 29, 2014 9:20:40 GMT -5 naughtyhorse said:

What's going on there is they built the tower in the wrong place! strictly speaking a suspension tower (one where the insulators hang vertically) can take an angle of deviation of 2 degrees - but the insulators swing over to one site and look a bit daft.

Whoops! That could have turned into an expensive mistake. I presume that line planners must have a process to ensure they place the towers correctly, so in this case someone must have been misreading their equipment or getting their calculations wrong.

[naughtyhorse]

Speaking as an overhead line designer, I would have to say, that would be a construction error :-)

due to the weird nature of overhead lines there are any number of ways such an error could be made.
typically a tower is located within 10mm of where the designer put the cross on the map.
these days with GPS it's not such a complex task. but in the bad ol days it was much more complex.

ordinarily in civil engineering a site is contained - a plot of land for a building for example. surveyors can then establish a set of benchmarks to take measurements from, knowing exactly where the benchmarks are (relative to one another) means you can do all manner of clever geometry to work out where everything else is, relative to your benchmarks. you just crate triangles of measurements and check to see the triangles 'work' properly

for overhead lines this approach wont work - to start with you need line of sight... imagine trying to find somewhere that you can see an entire line from!
the solution (I think it's called an open traverse) relies on careful measurement and NOT 'closing the triangle' which is the traditional method of checking for accuracy. create a triangle of measurements and then use trig to see that the angles and line lengths all make sense, if they do, you are probably ok, if they don't, you have made a mistake.
that said towers are usually locates pretty accurately.
well it's pretty easy to spot if they aren't.