Pylons .

[L2's are great!]

Its clearer to see here because you can see the spacers are angled diagonally rather than straight.

[pharrc20]

4 hours ago, L2's are great! said:

Another finding of recent is the rather different looking position of the insulators particularly with the D10s and D30s on the Hutton-Harker route. Either that or there are strong winds up there.

 

Rotated bundle conductors to reduce wind loading in high wind conditions. Quite a few lines on higher elevations have these now on twin conductors. Part of ZP and ZQ are the same too. Makes them look odd I know.

 

Cheers Paul

[L2's are great!]

3 hours ago, pharrc20 said:

Rotated bundle conductors to reduce wind loading in high wind conditions. Quite a few lines on higher elevations have these now on twin conductors. Part of ZP and ZQ are the same too. Makes them look odd I know.

 

Cheers Paul

Ahh I had a strong feeling it had something to do with the wind as that line runs through some steep valleys just north of Hutton sub. They certainly caught me out first time I saw them I suddenly thought L2 can take quad??

[L2's are great!]

Tynemouth Sub and always a delight to find another D90, just up from the one close to the Tyne crossing.

[L2's are great!]

And then this rare circumstance of a D90 on the XF line. D90's on L3 lines are very uncommon hence they just used the L2 variant.

[pharrc20]

20 hours ago, L2's are great! said:

Ahh I had a strong feeling it had something to do with the wind as that line runs through some steep valleys just north of Hutton sub. They certainly caught me out first time I saw them I suddenly thought L2 can take quad??

That is one of the cons for the L2 design as it can be subject to conductor galloping and clashing in extreme weather conditions and partly why they tried to develop the L2c Coventry type towers but presumably CEGB asked for a totally new design, which after some Scottish trial lines became the L8 and later L8c versions, with the longer middle crossarms that would prevent the lower and middle clashing and the middle and top phases clashing.

[L2's are great!]

11 minutes ago, pharrc20 said:

That is one of the cons for the L2 design as it can be subject to conductor galloping and clashing in extreme weather conditions and partly why they tried to develop the L2c Coventry type towers but presumably CEGB asked for a totally new design, which after some Scottish trial lines became the L8 and later L8c versions, with the longer middle crossarms that would prevent the lower and middle clashing and the middle and top phases clashing.

Interesting how the L3c was much more achievable although just for the D2 tower type, and I can only imagine the troubles and some of those towers are on very steep inclines. 

[pharrc20]

5 hours ago, L2's are great! said:

And then this rare circumstance of a D90 on the XF line. D90's on L3 lines are very uncommon hence they just used the L2 variant.

Makes you wonder why they didn't have a D90 in the L3 range or the other types of the DT and DJ towers. There is a nice L3 DJ tower at Stafford and another can be seen alongside the M6 near to Walsall, just to north of Bescot Yard where the L3 crosses over and runs parallel with a tee off. But not many like that. Even rarer are L66 DT towers though I think one might exist still at Harker really need to go check it out

[pharrc20]

2 hours ago, L2's are great! said:

Interesting how the L3c was much more achievable although just for the D2 tower type, and I can only imagine the troubles and some of those towers are on very steep inclines. 

Yes they seemed to make the L3 into L3c with extended middle crossarms a lot easier than for the L2s

[L2's are great!]

28 minutes ago, pharrc20 said:

Makes you wonder why they didn't have a D90 in the L3 range or the other types of the DT and DJ towers. There is a nice L3 DJ tower at Stafford and another can be seen alongside the M6 near to Walsall, just to north of Bescot Yard where the L3 crosses over and runs parallel with a tee off. But not many like that. Even rarer are L66 DT towers though I think one might exist still at Harker really need to go check it out

I would of imagined that the likelihood of needing a D90 was minimal at the time and seeing as L2 and L3 came along in 1952/53 they standardised the D90 since the L3 was a lot slimmer than the L2 so designing a slimmed down D90 may have not been as effective as just using the L2 variant. Theres 2 more examples, one not far from Monk Fryston and the other at Beauly Sub.

 

Ahh yes I recall both of those and they definitely seem to be 'one offs'. I do believe there are two L66 DT towers at Fourstones sub and another at Stella West. At Harker the line appears to  terminate on an L2 DT45. However it looks like its been altered in recent years

[L2's are great!]

32 minutes ago, pharrc20 said:

Yes they seemed to make the L3 into L3c with extended middle crossarms a lot easier than for the L2s

The modified L2 D towers worked with extended middle crossarms but the deviation towers just didnt look right.

[L2's are great!]

Great view of the Denny-Longannet lines

[L2's are great!]

Screenshot from a fascinating video of dewired tower ZD1 at Staythorpe being removed in 1992, 

A quick peel at streetview shows the set up today and this L8 now the southern link between ZDA and ZD and with that D10 (ZDA2) also linking ZDA to ZD via that one off D90, im guessing that D10 used to route ZD onto that old DT but I can't work out where it would of been positioned and whether that L8 is the new ZDA1. Part of me also thinks that D10 used to be a D30 too aha.

Edited January 21, 2023 by L2's are great!

[L2's are great!]

Found some more interesting historical photos from the 1970s this time of the construction of the M69 and it shows the 4WP line yet I’m not sure if it’s the Coventry end or Enderby end. Surely must of been when the line fully ran between Enderby and Coventry. Makes me wonder if there ever was a diamond crossing near the site where the motorway now is.

Edited January 21, 2023 by L2's are great!

[pharrc20]

17 minutes ago, L2's are great! said:

Found some more interesting historical photos from the 1970s this time of the construction of the M69 and it shows the 4WP line yet I’m not sure if it’s the Coventry end or Enderby end. Surely must of been when the line fully ran between Enderby and Coventry. Makes me wonder if there ever was a diamond crossing near the site where the motorway now is.

Iirc there is a gap of one or two towers in the numbering of 4WP I think around the point where it would have crossed and dived under ZL. I haven't got the numbers to hand as need to go on laptop to check lists.

Cheers Paul

[L2's are great!]

On 21/01/2023 at 21:21, pharrc20 said:

Iirc there is a gap of one or two towers in the numbering of 4WP I think around the point where it would have crossed and dived under ZL. I haven't got the numbers to hand as need to go on laptop to check lists.

Cheers Paul

Ahh its a shame there is no photographic sources to show the old crossing

[L2's are great!]

 

 

Another interesting find

Edited January 23, 2023 by L2's are great!

[SHMD]

Thanks for that.

 

I don't think I really understood the term "vertigo" properly until now!

 

 

Kev.

:)

 

 

[L2's are great!]

12 minutes ago, SHMD said:

Thanks for that.

 

I don't think I really understood the term "vertigo" properly until now!

 

 

Kev.

:)

 

 

Ahaha yeah, incredible to think they did that work in casual wear with no safety nets, harnesses etc

[L2's are great!]

Trailing along the 275/400kv Feckenham to Penn route and theres a lot of tee's on this section. One heading to Kitwell and then these 2 both connecting to Bishops Wood. This tee setup is not as common with the half crossing and the main route crossing under the tee itself. 

[pharrc20]

2 hours ago, L2's are great! said:

Trailing along the 275/400kv Feckenham to Penn route and theres a lot of tee's on this section. One heading to Kitwell and then these 2 both connecting to Bishops Wood. This tee setup is not as common with the half crossing and the main route crossing under the tee itself. 

Yes they don't often do that sort of reverse tee, but I guess here it was necessary to do to keep the 275kV circuits forming the outer West Midlands ring intact and to allow the 400kV circuit intact. Only other place I can think of this in same area is over near Berkswell where you have the tee off the ZF line also on 275 as the eastern part of same West Mids 275 ring network around Brum.

[L2's are great!]

21 hours ago, pharrc20 said:

Yes they don't often do that sort of reverse tee, but I guess here it was necessary to do to keep the 275kV circuits forming the outer West Midlands ring intact and to allow the 400kV circuit intact. Only other place I can think of this in same area is over near Berkswell where you have the tee off the ZF line also on 275 as the eastern part of same West Mids 275 ring network around Brum.

Ahh that explains it! It is pretty much an intact ring although some of the lines are half and half examples oddly, maybe they were fully 400kv at the time but since then having had one half downgraded maybe? Ahh yes I can’t believe I didn’t see that one too aha

[pharrc20]

2 hours ago, L2's are great! said:

Ahh that explains it! It is pretty much an intact ring although some of the lines are half and half examples oddly, maybe they were fully 400kv at the time but since then having had one half downgraded maybe? Ahh yes I can’t believe I didn’t see that one too aha

Yep quite a few L2 lines that are 275 on one side of the tower and 400 on the other. Pretty much all of them on the main routes would have started on 275 with intention to uprate to 380 as designed but with new insulation and conductors certain key circuits on trunk route uprated to 400 in time to further enhance the Supergrid especially with the introduction of so many new 400 L6 based lines coming on stream in mid to late 60s into the 70s. I guess any L2 lines built new in 70s would have tended to be more local secondary lines like Cellarhead to Crewe, Kearsley to Bury, Kearsley to Atherton capable of 275 but running on 132 only.

[L2's are great!]

23 hours ago, pharrc20 said:

Yep quite a few L2 lines that are 275 on one side of the tower and 400 on the other. Pretty much all of them on the main routes would have started on 275 with intention to uprate to 380 as designed but with new insulation and conductors certain key circuits on trunk route uprated to 400 in time to further enhance the Supergrid especially with the introduction of so many new 400 L6 based lines coming on stream in mid to late 60s into the 70s. I guess any L2 lines built new in 70s would have tended to be more local secondary lines like Cellarhead to Crewe, Kearsley to Bury, Kearsley to Atherton capable of 275 but running on 132 only.

So there would of been an intention to fully convert all 275kv L2 lines to 380kv and then to 400kv when it was realised L2 could take 400kv. But I imagine they never got round to all of them so left the half and half ones as they were with more focus being put on the L6s when they came around.  But in recent years those later 1970s L2 routes gained even smaller insulators and conductors after refurb and I've always thought they don't look right.

[pharrc20]

24 minutes ago, L2's are great! said:

So there would of been an intention to fully convert all 275kv L2 lines to 380kv and then to 400kv when it was realised L2 could take 400kv. But I imagine they never got round to all of them so left the half and half ones as they were with more focus being put on the L6s when they came around.  But in recent years those later 1970s L2 routes gained even smaller insulators and conductors after refurb and I've always thought they don't look right.

I suppose you have to think of the major city ring circuits would be 275 like Manchester, Birmingham, even Leeds/Bradford too. Some of London was but a lot has I think been upgraded to 400. Most of the trunk routes running from the Trent and Aire valley power stations going down south were 400 simply to transmit more power and later reinforced by the L6 lines too.

So the thinking to build the L2 Supergrid with 380 operation in mind to future proof the grid has to be commended. I don't actually know if any L2 lines operated or were tested at 380 but I would imagine some testing must have taken place. But only to pave the way to 400 once they realised the future L6 based Supergrid had to operate at 400 from the start.

It does look odd where you have different length insulators on the same tower. Like YV 47R near where I grew up which still runs 275 on one side with short ins and 400 on the far side with longer ins as per attached photo I took the other week when passing in the car.