ECML vs GWML Electrification masts

[Spaceflower]

I know that ECML electrification was done on the cheap and the opposite appears to have been acheived out of west London, but why the difference in physical presence between the two? The latter appear very intrusive aesthestically too.

I'm also looking at electrification masts elsewhere (including on the continent) and nothing seems to parallel the over-engineered monsters that now dominate the GWML scene.

 

[edwin_m]

Worth taking a look at https://www.riagb.org.uk/RIA/RIA/Ne...er/Electrification_Cost_Challenge_Report.aspx and the linked report.

The Electrification Cost Challenge (ECC) report uses examples from the UK and internationally to show that the high costs seen on recent projects, including the Great Western Electrification Programme, can be avoided in the future. It suggests that significant increase in cost on some past projects like Great Western should be seen as a one-off, caused by an unrealistic programme of work, unpreparedness in using novel technologies resulting in poor productivity and a ‘feast and famine’ electrification policy.

 

[GRALISTAIR]

Time changes everything. Progress on many fronts shows. North of Weaver Junction masts etc different than south of there on the WCML for example. That was only 10 years or so. ECML 1984 to 1991 whereas GWML post 2012 . So nearly 30 year gap.

 

[swt_passenger]

I think a major criticism of the ECML four track sections was the decision to use headspans, and we now know they are a big problem when typical faults occur, because breaks in a headspan often cause all four sets of catenary to go out of alignment. The GW designers seem to have decided on portal frames on most of the four track sections, and they provide fully independent registration of the four sets of wires, and are much more tolerant of mechanical faults. Another feature of the GW designs is that the tensioning and wire run termination is done vertically above the tracks, rather than off to the side, and this leads to even more complex portals at those positions.

Then meanwhile on two track sections the ECML generally uses pairs of relatively lightweight single track cantilevers, but on the GW there are a lot of twin cantilevers that have a much larger single mast on one side, because it’s carrying a much longer cantilevers on which two sets of wires are mounted.

So the GW equipment on both four track and two track sections is much more conspicuous.

I can’t help feeling this discussion has happened a few times before during the original progress of the project?

 

[themiller]

I believe that a big factor in the over engineering of the GWML was the government trying to put all of the financial risk onto the contractors who, understandably, put up their prices to cover it whereas, on the ECML, the government of the day accepted the risk. It’s all smoke and mirrors to make the treasury look better but it comes at a cost to the nation (taxpayers)!

 

[jfowkes]

It's probably no bad thing. If traffic levels are going to increase (as I hope they will) and as climate change causes more extremes of weather, "over-engineered" is going to become just "well-engineered".

 

[GRALISTAIR]

It's probably no bad thing. If traffic levels are going to increase (as I hope they will) and as climate change causes more extremes of weather, "over-engineered" is going to become just "well-engineered".

I totally agree with these sentiments.

 

[Western Sunset]

Wasn't the GWML electrification capable of 140mph? But then again, so was the original concept for the ECML.

 

[swt_passenger]

Wasn't the GWML electrification capable of 140mph? But then again, so was the original concept for the ECML.

It’s not just max speed, it’s how many pantographs are going to be used by the expected rolling stock. A 12 car train of 3 EMUs or a 10 car train of 2 x 5 car 80x affects the OHLE differently to a single pan at 125 mph (or 140 mph). AIUI this is basically why the southern MML needs so many upgrades.

 

[LNW-GW Joint]

Wasn't the GWML electrification capable of 140mph? But then again, so was the original concept for the ECML.

The catenary was designed for 140mph, at least west of the Cotswolds, but the existing track and signalling was not.
The intention was that the GWML would go to ETCS to provide cab signalling (and replace GW ATP), but that project was cut back to Paddington-Heathrow.

 

[JamesT]

As I understand it the Series 1 OHLE was designed by a Swiss company. So they’ve decided that is what’s necessary, rather than someone in the UK “over-engineering” with no regard to existing examples.

 

[Spaceflower]

I see.

 

[Western Sunset]

It’s not just max speed, it’s how many pantographs are going to be used by the expected rolling stock. A 12 car train of 3 EMUs or a 10 car train of 2 x 5 car 80x affects the OHLE differently to a single pan at 125 mph (or 140 mph). AIUI this is basically why the southern MML needs so many upgrades.

Is that one reason why APT-P was configured the way it was, with both the non-driving motors positioned adjacent to each other in the centre of the unit, so only one pan was required to pick-up the juice?

 

[swt_passenger]

Is that one reason why APT-P was configured the way it was, with both the non-driving motors positioned adjacent to each other in the centre of the unit, so only one pan was required to pick-up the juice?

Possibly, but I’m not at all familiar with the APT. Someone here will probably have an idea though.

 

[edwin_m]

Is that one reason why APT-P was configured the way it was, with both the non-driving motors positioned adjacent to each other in the centre of the unit, so only one pan was required to pick-up the juice?

Yes. There was a 25kV feeder between the two power cars at roof level.

Pendolinos and 80x have pantographs near each end and a similar feeder over the entire length in between, so that one pantograph can feed all motor cars in the unit. However, as far as I'm aware nobody tries to feed traction power between coupled multiple units, so a 2x5-car set will have two pans raised.

 

[Pigeon]

The GW kit does seem to have been designed with callous disregard for the eyeballs of anyone having to look at it, to a far greater degree than is usually the case for overhead equipment. Use a SQUARE lattice truss like a complete divvy, then make it thick and chunky so it still works, and then paint it white??? I refuse to believe its terrible appearance is any kind of unavoidable byproduct of engineering constraints.

 

[stuu]

The GW kit does seem to have been designed with callous disregard for the eyeballs of anyone having to look at it, to a far greater degree than is usually the case for overhead equipment. Use a SQUARE lattice truss like a complete divvy, then make it thick and chunky so it still works, and then paint it white??? I refuse to believe its terrible appearance is any kind of unavoidable byproduct of engineering constraints.

They are an appalling example of industrial design, to use the word most loosely. But they definitely aren't painted white

 

[Pigeon]

The arm in the attached screenshot looks pretty white to me...

 

[Phillipimo]

The GW kit does seem to have been designed with callous disregard for the eyeballs of anyone having to look at it, to a far greater degree than is usually the case for overhead equipment. Use a SQUARE lattice truss like a complete divvy, then make it thick and chunky so it still works, and then paint it white??? I refuse to believe its terrible appearance is any kind of unavoidable byproduct of engineering constraints.

This is an interesting talk from the Permanent Way Institution YouTube channel titled "Great Western electrification: why are the masts so big?

It covers details which may not be obvious at first glance. For example the TTC* structures in that picture were designed for quick installation to maximise what could be done in overnight possessions, the horizontal booms simply drop into place.
They were not designed to be ugly, they were designed to meet a challenging specification.

*Twin Track Cantilever

 

[Transilien]

I wonder if extensions to GWR electrification will be done with series 1 equipment or the more standard series 2?

 

[stuu]

The arm in the attached screenshot looks pretty white to me...

Just an effect of the photo, they definitely aren't painted. Someone more knowledgeable will know but I think they are a different material or have a different coating to the masts

 

[ac6000cw]

Just an effect of the photo, they definitely aren't painted. Someone more knowledgeable will know but I think they are a different material or have a different coating to the masts

It looks like galvanised steel (i.e. coated with zinc as corrosion protection) to me, which is light grey and fairly reflective when new, but weathers slowly to a darker, duller, grey.

 

[zwk500]

It looks like galvanised steel (i.e. coated with zinc as corrosion protection) to me, which is light grey and fairly reflective when new, but weathers slowly to a darker, duller, grey.

The only station with an island platform between the reliefs and nothing on the mains on the electrified section of the GWML I could find is Burnham, and recent stock photos certainly show the electrification around there having weathered, but the arms are still shinier than the larger structural parts:

(Stock photo of class 345 departing Burnham station take from the platform showing grey Electrification masts and gantries, listed as being taken on 4 May 2022).

Link: https://www.alamy.com/burnham-sloug...ae0ff55b83aaf78201b2c71547657dd3&searchtype=0

 

[LNW-GW Joint]

This is an interesting talk from the Permanent Way Institution YouTube channel titled "Great Western electrification: why are the masts so big?
It covers details which may not be obvious at first glance. For example the TTC* structures in that picture were designed for quick installation to maximise what could be done in overnight possessions, the horizontal booms simply drop into place.
They were designed to be ugly, they were designed to meet a challenging specification.

I don't think any part of the GW electrification project could be described as "quick installation".
The low productivity of the high output equipment led directly to delays and increased cost of the project.

The first wiring projects in the north west (Manchester-Newton le Willows-Liverpool and Huyton-Springs Branch) used Series 2 (good for 100mph) and traditional construction methods. and was done much more efficiently than the Series 1 and later projects.
The current MML and TRU projects still look overengineered to me, compared to recent 230km/h Swiss and Austrian main line schemes.

 

[ac6000cw]

The only station with an island platform between the reliefs and nothing on the mains on the electrified section of the GWML I could find is Burnham, and recent stock photos certainly show the electrification around there having weathered, but the arms are still shinier than the larger structural parts:

For reference (in the photo), I'm pretty sure the tubular post supporting the mirror in the right foreground is hot-dip galvanized (the grey blotchy crystalline patterning is characteristic of that), as is the palisade fencing at the end of the platform (and probably the nearest vertical electrification post, but it's a bit too blurry to tell for sure).

There's some photos of 'Series 1' OHLE equipment and installations on the Furrer+Frey website - https://www.furrerfrey.ch/en/service/series-1/ . It looks like some of the small diameter tubular items might be stainless steel or aluminium - note the difference in appearance of the metal components on either side of the insulator:

 

[Phillipimo]

I don't think any part of the GW electrification project could be described as "quick installation".
The low productivity of the high output equipment led directly to delays and increased cost of the project.

Indeed! Designing for quick installation didn't mean it turned out that way in practice! Although I believe most of the delays on the GWEP were with piling, rather than installing the masts and booms etc.

 

[Spaceflower]

I wonder how they will compare when it comes to maintenance costs?

That will be the key indicator of whether it is 'over-engineered'.

 

[Fidelis]

I wonder how they will compare when it comes to maintenance costs?

That will be the key indicator of whether it is 'over-engineered'.

When the design was announced the principal concern was to avoid the damage to one ole affecting the other three lines on the GWML. This has proved to be successful in recent incidents.

 

[QueensCurve]

As I understand it the Series 1 OHLE was designed by a Swiss company. So they’ve decided that is what’s necessary, rather than someone in the UK “over-engineering” with no regard to existing examples.

Strangely enough, Swiss OHLE is much less overbearing than the GWML.

They were not designed to be ugly, they were designed to meet a challenging specification.

They remain, however, ugly.

 

[themiller]

Strangely enough, Swiss OHLE is much less overbearing than the GWML.

Probably because the original design was carried on through to completion instead of changing part way through because someone new had a whizzy idea to try to save costs which usually ends up costing more and looking like a dogs breakfast.