A promising future

Environmental aspects of the 51m consultation response, part 16

In this blog I will continue my review of what Southdowns Environmental Consultants Ltd has said in Appendix 18 to the 51m alliance response to the public consultation (available here), which refers to criticisms that I have already made in earlier blogs.

In “We don’t believe you” (posted 25 May) I queried why the noise levels had been calculated on the basis of the source pass-bys being at a maximum speed of 360 kph, when the design speed was 400 kph. Needless to say, the Southdowns report also comments on this discrepancy.

“Operational speeds used in the HS2 noise model were supplied by HS2 Ltd and a maximum operational speed of 360kph has been assumed where track design speeds are over 360kph. The reasons for this assumption are not known given, in particular, the project’s evident aspiration for trains to run at 400kph where the design speeds and various statements on noise levels permit.”

The Southdowns report refers to the TSI for the infrastructure sub-system of the trans-European high speed rail system (2008/217/CE); this document may be downloaded here. In paragraph 4.2.19 (on page L 77/31), it says:

“The environmental impact of the projects concerning the design of a line specially built for high-speed or on the occasion of line upgrading for high-speed shall take into account noise emission characteristics of the trains complying with the High-Speed Rolling TSI at their maximum allowed local speed.”

Now I think that I know what that means, but I guess that it leaves just a little wriggle room that might allow HS2 Ltd to claim that the maximum allowed local speed will be 360 kph, at least initially. However, I don’t think that this interpretation really passes muster.

The Southdowns report looks at the statements that HS2 Ltd has made to justify this, beginning with the AoS and drawing the same blank as I did when I wrote “We don’t believe you”:

“No reason can be found in AoS Appendix 5.4 for an assumed limit of 360kph on day one of operation and its incorporation into noise calculation assumptions, other than for its inclusion in the HS2 Project Specification.”

The next document that Southdowns found to cite, the Consultation factsheet HS2 Trains(available here) is more enlightening:

“The Consultation leaflet on HS2 Trains states that the trains would initially travel at speeds of up to 360kph, but that train speeds could reach 400kph in the future on the condition that there would be no unacceptable increase in noise levels.”

However the word “unacceptable” is, to a sceptic like me, open to interpretation; who is to judge what is “unacceptable?

Perhaps better assurance has been found by Southdowns:

“This differs in precise wording to the commitment provided in the Consultation document which states that speeds above 225mph (360kph) would not be allowed unless impacts of operation could be demonstrated to be no worse than currently assumed for operation at 225mph. Furthermore, the latter statement suggests that the presentation of impacts in the AoS will provide the benchmark against which future train speeds of 400kph will be judged.”

That at least is, it appears, a positive and measureable commitment. The problem is will this commitment be remembered in twenty or thirty or more year’s time when speeds are increased? Even if this commitment is remembered, who will verify that it has been honoured?

How much will noise increase with speed, assuming for the sake of argument that there are no design improvements leading to quieter trains? In “We don’t believe you” I used some work by the Ladbroke action group to estimate that it would be “in excess of 2 dB higher”. The Southdowns report comes up with an increase of 3 dB. So we are talking about a “noticeable noise increase”.

The final verdict in the Southdowns report is:

“For the reasons set out in this report regarding calculation methodology and appraisal criteria, the derivation and presentation of assumed impacts is suspect and is not considered to provide an appropriate benchmark for future train operations at 400kph. Furthermore, application of the HS2 threshold for noticeable noise change (≥3dB) may be deemed to apply with regards to any definition of unacceptable increase and further clarification and commitments are required from HS2 to ensure that there are no future increases in HS2 noise impacts due to increased train speeds and/or traffic intensification.”

As a postscript to this you may be interested to know that in November last year I asked my MP to write to the Transport Secretary and ask him for his assurance on this matter; of course, this request pre-dated the commitments in the two documents referred to in the Southdowns report. More than six months later I received a reply, of sorts, that included the following:

“I take noise very seriously and have instructed HS2 Ltd to limit wherever possible the impact of this. They have been working with sound engineers to model sound impacts along the line of the route to better inform residents of any likely impacts. I hope your constituent will be able to attend a consultation roadshow event and hear for himself the work we have been undertaking. Any decision on future train speeds would have to be taken in the context of future developments in train design.”

Hardly worth the wait, was it?


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