Rising electrification costs caused by increased overhead electrification clearances

[ac6000cw]

Just been reading the latest Roger Ford 'Informed Sources' preview email. One item in there is:

Mindless regulation threatens electrification

In 1956, British Railway’s Chief Electrical Engineer Mr S.B Warder made a bold and far sighted decision. The pre-war Weir committee had recommended 1,500 Volt direct current electrification as the future standard. But with the French pioneering high voltage alternating current electrification for the re-equipment of their war-torn network, BR decided to follow suite for the electrification schemes proposed in the 1955 Modernisation Plan.


But high voltage had a particular drawback for a network built to a smaller loading gauge than continental railways. Electricity has an insatiable desire to return to earth, and the higher the voltage the greater the ability to arc to the nearest earthed object.

To calculate clearances for the 25kV OHL BR took the International Union of Railways standard of 320mm as its starting point and soon discovered that raising bridges to provide this clearance would be prohibitively expensive. Reducing the voltage to 6.25kV where raising a bridge was unaffordable caused the early problems with ac electric trains.

In a series of tests, in conjunction with Her Majesty’s Chief Inspector Officer of Railway’s, Brigadier C A Langley, Stanley Warder investigated the possibility of reducing clearances. The final test in Crewe tunnel confirmed that with a 50mm air gap 25kV would not flash over, even when subjected to the full blast from a steam locomotive chimney.

As a result, in August 1962, new reduced standards, were authorised, permitting clearances of 200mm at particularly difficult locations. This cut the cost of clearance works on the London-Liverpool/Manchester project by around 7%,

Two decades later, on the East Coast Main Line electrification, 200mm had become the new ‘Normal’ minimum clearance with a ‘Reduced’ minimum of 150mm. Railtrack’s revised electrification Group Standard published in 2001 increased the ‘Normal’ minimum to 270mm while retaining the BR clearances as ‘Reduced’ amd ‘Special Reduced’.


Today
Three decades on and clearances are causing major problems. On 21 September this year the Scottish Parliament’s Rural Economy & Connectivity Committee took evidence from the ScotRail Alliance. Ahead of the hearing ORR provided the Committee with its latest review of the Scots’ electrification projects and one of the main reasons for schemes running late and over budget was the late identification of the scope necessary ‘to achieve a safe and sustainable railway through compliance with legal obligations and European standards’.

By now I hope you can see the reason for my historical introduction. For ‘compliance scope’ read ‘electrification clearances’. ORR claims that this scope is important ‘as it affects the ability to run a safe and sustainable railway’.

As you might imagine, the relevant European Technical Specifications for Interoperability (TSI) have something to say about electrification clearances. Until 2015 the UK had a National exemption from the relevant European Energy (ENE) TSI.

However, when the relevant Network Rail standard (GL/RT1210) was reissued in April 2015 the requirements of the ENE TSI came into force under the UK’s interoperability legislation raising the normal minimum clearance to 370mm which is being applied retrospectively to on-going schemes.

This is how ScotRail Alliance Chief Executive Phil Verster explained what happened next to the September 21 hearing.
‘Network Rail attempted to keep costs down by saying that the new specification is really high and asking whether it could risk assess things in order to get a derogation and therefore not to have to comply. Last year, when all the shenanigans started and the cost issues became really clear, it became obvious to the ScotRail Alliance and to me that if we did not comply with the standards the ORR would not sign off the line to go live: if we had continued to debate the matter, we would have got late into the programme and built the railway only for the ORR to say that we could not run anything on it’.

Trapped in a three way bind between the Economic and Safety regulators and Transport Scotland, in March this year Phil instructed the EGIP Project team ‘Stop the debate and move to the new standard. The railway will have hundreds of years of life into the future, so fix this now’.


And it’s not just tunnels and bridges. The distance between any live part of the OHLE or pantograph and any place a person might stand has also been increased from 2.75m to 3.5m (11ft. Having received a policy statement from ORR I’ll return to this requirement in a future column.


Risk
So how have we come to the situation where, after more than 50 years since those tests in Crewe, with the progressive reduction in clearances making electrification within our smaller loading gauge affordable, we are now back, not just to the clearances in UIC606 but another 50cm on top?

Why did not Network Rail see it coming and gain derogations to continue with the clearances in GL/RT1210 on the grounds that electrification has an excellent safety record and we don’t have the air-space of mainland European Railways? One Informed Source suggested that Network Rail could not mount a challenge because the records justifying historic clearances had disappeared in the sell-off of the British Rail engineering offices under privatisation.

What makes me genuinely angry about this ludicrous situation is that after the struggle to get electrification back on the agenda, and many readers signed up to my petition on the Number 10 website, the pass has been sold.

And that includes ALARP (As Low As Reasonably Practical) seemingly going out of the window. Interestingly, when I started a Twitter debate over the cost of the new clearances, I came under fire on the grounds that I was arguing for the UK to be ‘less safe’ than Europe, just to make electrification more affordable.

But this assumes that the Government will authorise electrification at any price. Which they won’t. And funding for the next Control Period is getting ever tighter.

I would risk a modest bet on Swansea not getting electric trains in Control Period 6 (2019-2024. And given slightly better odds make it a double with Trans-Pennine electrification.

Meanwhile, I would be grateful if any reader can provide a reference for a passenger on a platform being electrocuted by contact or flashover with 25kV ac OHLE or a pantograph.

As an engineer, it does seem a slightly odd situation to have ended up in, after 50+ years of 25kV overhead electrification in the UK - any comments from people who understand the technical reasons for this ?

(Please, no 'Brexit' related political comments - there are other threads for that).

 

[swt_passenger]

This has all been discussed already in the EGIP thread hasn't it? Roger's article isn't new news here...

 

[YorkshireBear]

The reasons for it are very much unknown. Clearances are being increased massively but I am yet to see anyone justify it. Unfortunate incidents recently with foil helium balloons and potential from Umbrellas has caught the eyes of the regulators.

Part of it is also to try and discourage suicide. Although as Roger says, evidence that this happens does not seem to be forthcoming.

Overall, this is an absolute minefield which Network Rail has found itself in with no cheap way out. Infact there is not even an easy way out.

I reckon if CAF can get the Northern DMUs working well and Stadler the AGA Bi Modes we could see those becoming two major rolling stock manufacturers in the UK as we realise we can no longer afford to electrify.

If I can bring BREXIT into it momentarily (mainly to justify you saying that BREXIT isn't part of it). The DfT has been told that the railways are very low down on the Agenda when it comes to amending laws etc from us leaving the EU so there is no discussion about Brexit to be had. The current laws will be with us for at least another 5 years without any changes. That has come from a presentation on the subject i know nothing more so as the OP requested lets leave it out.

 

[Camden]

The laws might be low down on the list in terms of amendment, but then again without any EU obligations to worry about so too might be their enforcement?

The country needs an overarching creative law that allows EU regs in all areas of commercial operations to be disregarded if it is deemed "onerous" or likely to be subject to repeal or review. Then all it would need is some legal advice that stands up to scrutiny.

 

[snowball]

This has all been discussed already in the EGIP thread hasn't it? Roger's article isn't new news here...

It's been discussed in several threads, and originally in the Blackpool-Manchester electrification thread, starting on 27th June, page 189. I emailed Roger Ford about it on 21st July suggesting he might want to investigate and write about it. He replied saying he might, but he listed a number of other things he was hoping to cover over the next few months.

Other than his e-preview, which I've also received but haven't read yet, the most informative thing I've seen about it recently is the Scottish Parliament document linked from this post by clc in the Aberdeen-Inverness upgrade thread:

http://www.railforums.co.uk/showpost.php?p=2737886&postcount=28

 

[ac6000cw]

It was this comment in particular that was of most interest:

So how have we come to the situation where, after more than 50 years since those tests in Crewe, with the progressive reduction in clearances making electrification within our smaller loading gauge affordable, we are now back, not just to the clearances in UIC606 but another 50mm on top?

It's quite understandable when starting out on something new (that you have little or no practical experience of) that you 'play safe' and hence go for large clearances in the late 1950s. As experience and testing builds up, it's again natural that you try and reduce costs where you can (without compromising safety) - that's normal engineering development and progression.

But why has the (already generous) 'standard' European clearance increased over the last 50 years from 320mm to 370mm - it doesn't make much sense in relation to experience?

(The 'political' fallout from this has already been covered on other threads - it's the technical background reasons I'm curious about).

 

[GRALISTAIR]

Thoroughly depressing

 

[Joseph_Locke]

I think you'll find the requirement to provide 370mm has been around a long time, but the UK had a long-standing national exemption to it. This exemption has now been withdrawn, after the current round of electrification was being budgeted for but just before most of it started construction.

The actual full-compliance value is 600mm, btw. :roll:

 

[ac6000cw]

The actual full-compliance value is 600mm, btw. :roll:

Ouch...(in cost terms at least).

I wonder how much (non-UK) railway electrification actually complies with that?

 

[Phil.]

Ignore the Europe bit.
Our country, our rules. Why should something that's proven to be safe and satisfactory be changed?

 

[rebmcr]

Ignore the Europe bit.
Our country, our rules. Why should something that's proven to be safe and satisfactory be changed?

Poe's Law seems to apply.

 

[Joseph_Locke]

I wonder how much (non-UK) railway electrification actually complies with that?

By non-scientific observation, (.2 x naff all).

By way of a striking coincidence, all non-compliances to the un-exempted value can be risk-assessed away - does make you wonder what the risks actually are, doesn't it?

 

[snowball]

This has all been discussed already in the EGIP thread hasn't it? Roger's article isn't new news here...

Now I've read it I can say there's one bit that's new to me:

Why did not Network Rail see it coming and gain derogations to continue with the clearances in GL/RT1210 on the grounds that electrification has an excellent safety record and we don’t have the air-space of mainland European Railways? One Informed Source suggested that Network Rail could not mount a challenge because the records justifying historic clearances had disappeared in the sell-off of the British Rail engineering offices under privatisation.

 

[edwin_m]

Two separate issues here I think.

Clearances to structures should be the easy one. There is no uncertainty about the measurement and even if flashover occurs it is more of an operational inconvenience than a safety issue. So it should be possible to reduce them to any value that can be justified by testing.

The issue that I thought was more significant is clearances to people. There is a historic trend of people getting taller so there may be some justification in increasing the clearances, although I'm not aware of any electrocutions of people on platforms. But the way the change has been made is a real mess. As I understand it standards are usually agreed at the time of signing a contract, with later changes only if really esssential and accompanied by reimbursement of extra cost incurred. The same should apply here with the "contract" being between NR and some government body (ORR?).

 

[Tio Terry]

Current clearances are very much determined by BS EN50122, the Energy TSI is the ERA's way of applying the requirements of EN50122 when it comes to the safety aspects of bare conductors. The principles are clearance by air gap (especially for members of the public) and the positioning of "obstacles" where clearance cannot be achieved. Even given a so called Hard Brexit it is most unlikely that any organisation with responsibility for public safety will ever recommend any form of reduction of the clearances recommended in EN50122 for safety reasons.

In terms of air gap to infrastructure all new construction will need to meet the standard set out in the TSI, this also meets EN50122. For existing infrastructure there is all ready case study to show that the ORR are happy to go along with the Explicit Risk Estimation (ERE) route allowed by EN50122, this has been applied to the electrification of Paddington Platform 14 where the existing infrastructure would not allow anything like the recommended air gaps. The way in which "obstacles" are to be provided at this location has still to be finalised.

If NR applies EN50122, including the option of ERE's, it should be possible to continue to electrify existing infrastructure in all but the most difficult of locations without resorting to massive expenditure.

 

[ac6000cw]

For existing infrastructure there is all ready case study to show that the ORR are happy to go along with the Explicit Risk Estimation (ERE) route allowed by EN50122, this has been applied to the electrification of Paddington Platform 14 where the existing infrastructure would not allow anything like the recommended air gaps. The way in which "obstacles" are to be provided at this location has still to be finalised.

If NR applies EN50122, including the option of ERE's, it should be possible to continue to electrify existing infrastructure in all but the most difficult of locations without resorting to massive expenditure.

So does the 'ERE' have to be estimated separately for each low bridge, tunnel etc. where you might want to apply it, or can it be a 'route' thing?

 

[Tio Terry]

So does the 'ERE' have to be estimated separately for each low bridge, tunnel etc. where you might want to apply it, or can it be a 'route' thing?

Being "Explicit" infers it's per site, however, where sites have the same issues NR have been successful in arguing that, in accordance with CSM-RA rules, that previously accepted sites under ERE can be classified as "Reference Systems" but you do have to demonstrate there are no significant differences.

 

[snowball]

Now I've read it I can say there's one bit that's new to me:

Why did not Network Rail see it coming and gain derogations to continue with the clearances in GL/RT1210 on the grounds that electrification has an excellent safety record and we don’t have the air-space of mainland European Railways? One Informed Source suggested that Network Rail could not mount a challenge because the records justifying historic clearances had disappeared in the sell-off of the British Rail engineering offices under privatisation.

Now the printed mgazine is out, and this statement from the e-preview doesn't seem to be in the full article.

 

[GRALISTAIR]

Why did not Network Rail see it coming and gain derogations to continue with the clearances in GL/RT1210 on the grounds that electrification has an excellent safety record and we don’t have the air-space of mainland European Railways?

This bit is in my iPad electronic version downloaded today.

 

[snowball]

Why did not Network Rail see it coming and gain derogations to continue with the clearances in GL/RT1210 on the grounds that electrification has an excellent safety record and we don’t have the air-space of mainland European Railways?

This bit is in my iPad electronic version downloaded today.

And in the paper version, but in answering his own question he doesn't mention loss of records.

 

[LNW-GW Joint]

And in the paper version, but in answering his own question he doesn't mention loss of records.

But instead of blaming NR for losing the records, he has a go at the ORR for not being proactive to avoid the increased costs of compliance.

 

[Tio Terry]

But instead of blaming NR for losing the records, he has a go at the ORR for not being proactive to avoid the increased costs of compliance.

I would say that that is not at all fair. If records have been lost then its more likely to have been Railtrack rather than Network Rail and from what I've seen the ORR have been very pro-active and helpful, especially for Platform 13 at Paddington.

 

[snowball]

I would say that that is not at all fair. If records have been lost then its more likely to have been Railtrack rather than Network Rail and from what I've seen the ORR have been very pro-active and helpful, especially for Platform 13 at Paddington.

The printed column does indeed take swipes against Railtrack, and against the DfT in that era, naming John Edmonds and Sir John Armitt, but doesn't mention the loss of records - that's only mentioned under "one informed source says" in the e-preview.

His complaint about the ORR is that its safety regulation arm is insisting that NR must implement the higher clearances while its economic regulation arm is blaming NR for the resulting delays and cost increases.

 

[NotATrainspott]

I think the impact of this change upon future electrification schemes will be mitigated by the easy availability of batteries in future. The worst-case problem would be a station on one side of a busy road bridge in an area with a history of flooding. Dropping the track by enough to gain clearance would make the flooding worse unless expensive measures are taken, and raising the bridge would be expensive and disruptive for the surrounding community. Neutral sections wouldn't traditionally be acceptable here as trains will need to accelerate out of the station. With battery packs, the entire non-compliant section of overhead line could be neutralised and trains would use their batteries to reach the electrified section. The batteries would only need to be capable of moving the train a few hundred metres from a standstill, so would easily recharge in time for the next problematic section.

 

[Trog]

Lowering the track through a station is not a good idea regardless of flooding. As it means all the platforms have to be altered to match.

 

[Ploughman]

Lowering the track through a station is not a good idea regardless of flooding. As it means all the platforms have to be altered to match.

Unless the platforms are of a substandard height now.
Also it may be cheaper to lower the platforms rather than lift a bridge.
We lowered through Keighley station platforms rather than lift Station bridge.

 

[Verulamius]

The Office of Rail and Road published earlier in October their guidance on electrification clearances to standing surfaces. http://orr.gov.uk/__data/assets/pdf_file/0009/23004/electrical-clearances-policy-statement.pdf

 

[rebmcr]

The tram system in Prague has OHLE pressing against the metal understructure of bridges, with only a plastic shim in-between.

 

[PaulJ]

Just read this in today's Telegraph. As I'm a complete amateur as well being a healthy cynic, can anyone in the know put some meat on the bones of this story. What's the truth?

...In the sixties, BR did extensive testing on how far the overhead wire had to be from other objects to prevent electrical discharge. Finding that discharge was unlikely at a distance of two inches, they set the standard clearance at eight inches (200mm).

This was the standard used for both the West and East Coast main lines, and it has applied ever since.

In 2015 a new EU standard of 370mm was introduced, and the Office of Rail Regulation has said it will refuse to sign off electrification schemes not following the new standard, even if they have already started. This increased clearance, from 8 to 14.5 inches, means that bridges that could have been adapted will now need rebuilding, and tunnels whose track could have been lowered will now need to be enlarged.

It is therefore not surprising that costs have escalated

 

[snowball]

Just read this in today's Telegraph. As I'm a complete amateur as well being a healthy cynic, can anyone in the know put some meat on the bones of this story. What's the truth?

I assume you're not a regular reader of any of the electrification threads as it's been discussed at length several times in the last few months. That makes it difficult to know where to start to reply.

It's also an item in Roger Ford's column in the current Modern Railways.

However it's safe to say that the changed rules on electrification clearance are only one of a number of reasons for the escalating costs and timescales of electrification projects.