Dancing on the head of a pin?

WHETHER the subject is HS2, new houses in the green belt, or wind turbines and solar panels in the countryside – to take just a few examples – it seems that the principal environmental concern of most Britons today is the VISUAL impact of new developments.

Recently details have been released summarising public responses to the Environmental Statement accompanying the Birmingham-West Midlands’ HS2 hybrid Bill – which will have its Second Reading in the House of Commons on 28 April – and it shows that respondents’ greatest desire is to bury HS2 in tunnels where it can’t be seen. 

However, tunnelling (and construction of deep cuttings) requires massive machinery that generates carbon emissions – nevertheless, there is considerable public pressure for even more tunnelling than has been proposed.

As the analysis by Golder Associates has highlighted the many comments about tunnelling “are due to the specific campaign demanding a full length tunnel under the Chilterns AONB (Area of Outstanding Natural Beauty) supplemented by other respondents also calling for the same feature within their responses.”

Lengthening the Chiltern Tunnel – already planned to be 13.5 kilometres (8.5 miles) long – was the principal concern of more than half of the 21,833 responses.

But carbon emissions caused by tunnels and deep cuttings are also one of the reasons why the MPs’ Environmental Audit Committee (EAC) recently proposed that HS2’s operational top speed should be reduced from 360km/h to 300km/h (apparently overlooking that, to maintain frequency and capacity, additional trains might well be needed, consuming more energy and also producing carbon dioxide – and that along a third of the route between London and Birmingham the maximum permitted speed will never be more than 320km/h, anyway).

By my reckoning, the start-to-stop average speed of a non-stop HS2 train between Old Oak Common Interchange and the new station in Birmingham city centre will be 295km/h – with the maximum of 360km/h only allowed north of the Chiltern Tunnel, 45km from London, for just 100km to Birmingham Interchange. From there the maximum will be only 250/230km/h over the remaining 21km into the city centre terminus.

The other reason for the EAC proposing a lower top speed was the MPs’ concern about whether, or how quickly, Government action will be taken to decarbonise electricity generation – “a matter that has been largely absent from the HS2 debate so far,” according to the committee.

Yet Britain’s rail industry is already a principal user of low-carbon energy . . . following last year’s 10-year deal between Network Rail – the largest purchaser of electricity in Britain – and EDF, which means railway power demands are now matched to the low-carbon output of EDF’s eight nuclear generating stations.


The EAC’s proposals also seem to have ignored issues such as train weight and aerodynamics, not to mention that HS2 is expected to contribute only 0.15 per cent of all carbon emissions – so a debate about its carbon impact may be little more than dancing on the head of the pin in relation to reducing the UK’s total carbon emissions.

Moreover, an adviser employed by the EAC had previously worked for some of the project’s most voluble opponents.

On page 7 of their report, the MPs say they are “grateful for the assistance of our specialist adviser Dr William Sheate”.

A footnote then discloses: “Dr Sheate declared the following interests on 26 February 2014: Adviser to HS2 Action Alliance and Chiltern Conservation Board on the judicial review of HS2 and the HS2 Appraisal of Sustainability (2011-13); and project manager on Defra’s evaluation of the biodiversity offsetting pilot scheme in England (2012-14).”

I find it more than a little surprising that the EAC, if it was seeking to take a balanced view, should have employed someone who has been an adviser to two of the organisations most implacably opposed to HS2!

In so doing, the committee may well have overlooked sound arguments that the Department for Transport and HS2 Ltd had significantly underestimated the likely transfer of motorists and airline passengers to rail travel after HS2 is completed — an important consideration, since the average car journey results in three times more carbon dioxide per kilometre travelled than the equivalent train journey, and a short-haul air passenger produces even more CO2.

It also seems to me that the EAC has taken for granted arguments that basic physics mean energy consumption and carbon emissions simply increase with the square of any speed boost – while wider (equally physical) factors have not been taken into account.

For example, the MPs seem to have taken at face value evidence from the HS2 Action Alliance, stating: “HS2 Action Alliance estimated that an HS2 train travelling at 360km/h would use three times as much energy as an Inter-City train travelling at 200km/h.”

That may be theoretically true – but no one has ever proposed that an existing train, such as a Pendolino operating now on the West Coast Main Line at 200km/h, would be operated at 360km/h on HS2.

For a start, the Pendolino is already a relatively big user of energy because of its weight, due to the equipment it must carry to tilt on the sinuous West Coast route.  But without tilt, it would be unable to maintain the shorter journey times that have attracted many new passengers (further proof, by the way, that faster journeys do attract passengers – often from their cars, provided there is also adequate parking for them).

However, HS2 trains will not be required to tilt, so its trains can avoid this weight penalty. And if HS2 trains are lighter they will have a lower energy demand, producing less carbon dioxide, to attain higher speeds.

HS2 will also enable trains to be longer – up to 400 metres compared to the Pendolinos’ maximum of 250 metres, a limit dictated by platform lengths due to Britain’s confined structure gauge and Victorian track layouts.  Longer trains carry more passengers and also produce less aerodynamic drag – especially if fitted with bogie ‘skirts’ and flush covers between the coach ends.  These factors, linked with the limited stopping patterns planned for HS2 (requiring less energy because there will fewer spells of intense acceleration), all contribute to reducing energy demand.


The list of written evidence submissions to the Environmental Audit Committee does not include the report prepared five years ago for Greengauge 21 by the Association of Train Operating Companies on ‘The CO2 impacts of High Speed Rail’. But its contents are highly significant.

For example, the ATOC report states: “One way of mitigating the energy penalty for high speed trains is to ensure a high seat capacity, so that the energy per seat kilometre compares favourably with that of slower, conventional trains.”

ATOC points out that Japanese Shinkansen 700 trains – developed in the mid 1990s, even earlier than Fiat’s (later Alstom’s) Pendolinos – consume less energy and produce less CO2 per seat/km at 300km/h than a Pendolino at only 200km/h. This is partly due to the Shinkansen’s lighter-weight construction but also because of its radical aerodynamics, including the characteristic ‘duck-billed’ front-end design, which significantly offsets drag and energy consumption at higher speeds.

HS2 Ltd has based its plans on a ‘reference train’ closer to home – Alstom’s Automotrice Grande Vitesse, with a designed top speed of 360km/h.  A fleet of 25 AGVs is already operating in Italy.

Ironically, perhaps, the AGVs were built at the same factory and alongside the recent additional Pendolinos for Virgin West Coast. But the AGV is more efficient – requiring no more power per seat/km at 300km/h than a Pendolino at only 200km/h.  This is because, according to ATOC, an AGV weighs in at only 0.78 tonnes per seat, whereas a Pendolino tops this at 1.05 tonnes per seat – 35 per cent heavier.

So it is quite unreasonable for HS2AA to blandly claim, and the committee of MPs to simply repeat, that an HS2 train travelling at 360km/h would require three times as much energy as an inter-city train at 200km/h.

Then there are the carbon emissions that will be saved when motorists – attracted by the benefits of HS2, including reduced journey times and the ability to do work that cannot be done behind the steering wheel – get out of their cars and into trains.

The ATOC report, produced five years ago, stated: “Any increased rail carbon emissions from operating faster trains therefore needs to be set in the context of the emissions avoided through reduced air and road travel and through the ability to use more carbon efficient modes to access rail terminals.”

The latest evidence by Greengauge 21 to the recent EAC inquiry said the Strategic Case for HS2 published in October 2013 showed that “based on the evidence of the National Travel Survey, the proportion of trips made by rail for journeys over 25 miles increased over the 15 year period from 1995 from 8 per cent to 14 per cent.”

Greengauge said this modal shift was ‘very significant’ but also pointed out that HS2 is now forecasting only a 4 per cent modal shift from car to rail when the new line is built.

Greengauge reckoned these latest forecasts were ‘unduly cautious’, adding: “With the additional capacity provided by HS2, we would expect a stronger growth in rail and in rail market share. But the modal growth levels in the HS2 Ltd demand forecasts are assumed to be unaffected by the capacity on offer.

“As a consequence the assessment of beneficial environmental impacts arising from significantly less car (and short-haul aviation) use, and significantly more use of the lower carbon rail mode, is under-estimated. The effect of capacity enhancement is only assessed in terms of supposed reductions in levels of overcrowding, and not in terms of the ability for rail to accommodate additional demand.”

But the Environmental Audit Committee seems to have taken little account of all this, stating instead: “There is some debate about whether HS2 will deliver a reduction in emissions by taking travellers off the roads and planes. But at best, the savings are likely to be relatively small.”

And it adds: “Perhaps a bigger issue is the potential effect of the decarbonisation of the generation of the electricity used by the trains; a matter that has been largely absent from the HS2 debate so far.”

But decarbonisation of electricity is not something within the control of HS2; rather, it depends on Government policy and actions.

However, there would be nothing to stop the operator of HS2 in 2026 signing a deal with its electricity supplier(s) that would ensure all or most of its power came from carbon-free (such as nuclear) and/or renewable sources.

Indeed, last year’s 10-year deal with between Network Rail – Britain’s largest purchaser of electricity – and EDF means that Britain’s railways are already using low-carbon electricity, with demand ‘matched’ to output from EDF Energy’s eight nuclear power stations. In the words of David Higgins, when he was chief executive of Network Rail, now chairman of HS2 Ltd, this is an “innovative contract for low-carbon energy”.

The reality is that rail is just about the most energy-efficient form of mass transportation – especially when powered by electricity, which it will be moving to increasingly during the next decade. According to Network Rail, 54 per cent of the network will be electrified by 2020 with electric trains then accounting for 75 per cent of all rail traffic, compared to 55 per cent now.

With HS2 only likely to account for 0.15 per cent of the UK’s overall carbon, perhaps the Environmental Audit Committee should focus rather more on tackling the remaining emissions – in other words, 99.85 per cent of them.

5 thoughts on “Dancing on the head of a pin?

  1. HS2 should start at the east side of Euston, run in tunnel to West Hampstead, on viaduct over the M1, alongside the WCML (an established railway route!) to Rugby and there forks west to Birmingham and Manchester. The nearest big town northwards from Manchester is not Glasgow or Carlisle nor Oxenholme. It is LEEDS! Why do we think otherwise? So the route goes 45 miles north-east to Leeds and is joined by the route from Rugby to go on to Scotland via the north-east, far more profitable than the Calisle route.

    Energy is a minor issue for HS2; It is calculated the energy needed to carry a passenger from London to Manchester costs only 60p! So it is not for that reason that I propose using Channel Tunnel Shuttle-size trains seating 3+3 on two decks. The reason for this size train is that trains of this size only 200 M long will can carry1.5 times as many passengers as HS2’s 400 M long trains. Building stations to take trains that size increases costs and disruption enormously.

  2. It is true that most objection to the building of all manner of things on greenfield sites is aesthetic. What is seldom heard or seen though, is the mpre prosaic problem of the loss of more and more agriculiural land .

    We cannor rely on always being able to import food freely , either for economic or for political teasons.

  3. May I comment on the comment from Michael Bell, rather than the very informative blog….
    Why is it that people think you can build a new railway line alongside an existing railway line (this is not the first time I have heard this). The existing line is slow and twisty, and is built up on either side (due to the success of the railways over the years, towns have crept out alongside the railway everywhere, try building a new railway through the middle of Milton Keynes or Northampton, and see how many houses you need to destroy, let alone the disruption to passengers on the existing line where bridges and tunnels have to be rebuilt). So we have a new railway built, more expensive than HS2, which is slower due to the twists. The new slow railway will not attract people off planes or cars due to the slow twisty nature of the new line. Then we get to Manchester and divert to Leeds (which is ENE of Manchester, not North). If the trains will be built to a totally different loading gauge it means trains on the new slow line alongside the old slow line could not be connected in any seamless integrated way. Other than that, it’s a great idea, but one which needs to be consigned to history along with the notion that people want to get from A to B slower, something that has been proven wrong time and time again since the first railway was built.

  4. As always, a stimulating and informative read. The high weight and complexity of tilt mechanisms also mean that an 11 carriage 320 kph AGV (as supplied to NTV in Italy) costs almost exactly the same as an 11 carriage 200 kph Pendolino as supplied to Virgin. Which is also about the same as an 11 carriage 225 kph IEP train to be supplied by Hitachi for the ECML and the Great Western Mainline. The AGV seems far and away the best option, provided there is a track it can run on…

  5. I suggest that those who talk about building beside an existing railway pay a visit to London Bridge Station and see how difficult just adding a normal sized two track railway beside an existing line and surrounded by building really is with a pub loosing its upper floors for the railway !

    Its often forgotten the level of demolition that occurred when the original railways we’re built and of course a few miles from the terminus they went through green fields !

    As for trains energy efficiency well we already have latest AGVs and TGVs to see in the real world and HS2 will use similar trains updated to when they are built in the next decade.

    The big failing in the above suggestion re a lower top speed is that Birmingham is only the end of Stage 1 with Stage 2 taking trains on to Leeds and Manchester and classic compatible trains all the way to Scotland some of which may not even stop until well past Birmingham .

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