beleben

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Carte blanche to misinform

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HS2 Ltd, 'integrity', in 2014 - 2017 corporate plan

In HS2 Ltd’s annual report and accounts 2014/2015, chairman David Higgins said, “We have to be open and transparent in communicating the benefits of HS2 as we see them“. According to senior officers of the company, one of the benefits of high speed rail is its ‘higher capacity compared to a conventional line’. At a meeting of the House of Commons Transport Committee on 17 November 2014, David Higgins said “a railway line where trains travel at 220 miles an hour as opposed to 120 miles an hour clearly has nearly twice the capacity because you can have twice as many trains on it. Once we started talking about capacity, then people started to get it“.

In an interview for The Rail Engineer article ‘Taking HS2 to completion’ (29 April 2016), the chief executive of HS2 Ltd, Simon Kirby, made a similar claim. He was quoted as saying that a conventional two track railway would have less capacity than a high speed one:

[Extract from Taking HS2 to completion]

[Rail Engineer:] Some people have questioned whether a high-speed railway is strictly necessary. If a conventional railway, with a speed of, say, 140mph, were to be built instead. Wouldn’t that do just as well?

[Simon Kirby:] “Most of the characteristics are the same for any type of new railway, the aesthetics of bridges and the substructure are the same,” Simon replied. “One of the challenges we all have as an industry is taking people into the world of three or four per cent passenger growth and imagining what the industry looks like in 10 or 20 years’ time. Half of the trains out of Euston by the end of this decade will be full, and that’s with standing provisions as well. So we’d need a four track railway from Euston to Birmingham, not a two track one, because the speeds are slower and the capacity is less.”

In freedom of information requests, HS2 Ltd were asked to provide any evidence held which supported the speed – capacity relationship described by Mr Higgins.

They have been unable to produce any.

So far as can be established, HS2 Ltd’s speed / capacity assertions do not have a factual basis.

One might have expected that the company’s “integrity” policy would lead to a public retraction of the claim. So far, nothing has been forthcoming.

HS2 Ltd seems to be taking the view that they have carte blanche to disseminate any misinformation they choose.

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Written by beleben

September 7, 2016 at 6:52 pm

Posted in High speed rail, HS2

One Response

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  1. The capacity of a plain level track can be calculated in terms of usable train paths per hour for various speeds using the methodology outlined in Andrew McNaughton’s 2011 paper. http://assets.hs2.org.uk/sites/default/files/inserts/hs2%20minimum%20headway%20august2011%20v3%201%20final.pdf At high speeds the dominant factor affecting capacity is stopping distance which increases with the square of the speed. Using A.McN’s value of deceleration (0.687m/sec2) the usable paths at 360kph is 23 but the maximum of 26 occurs at 200kph. In a paper produced by Bombardier http://assets.hs2.org.uk/sites/default/files/inserts/bombardier%20transportation%20hs2%20final_121011.pdf for HS2 it is suggested that lower values of deceleration should be used, for what seem very good reasons, and these have the effect of increasing stopping distance from 7.3km to 9.3km at 360kph. The increased stopping distance reduces the number of usable paths at 360kph to 19 with a maximum of 25 at 200kph. The capacity therefore falls much more at higher speeds with the lower deceleration rates proposed by Bombardier. In practice the actual usable paths per hour will be significantly less than that calculated for plain level track. With only 19 usable paths available on plain level track it is easy to see how gradients and junctions could result in a system that could not operate reliably at HS2’s claimed 18 trains per hour. It is a damning indictment of the lack of scrutiny that HS2 has received from politicians, scientists and engineers that HS2 can continue to peddle such blatant misinformation. If capacity is the alleged problem the optimum speed would seem to be about 200kph. Shorter signalling sections and ERTMS may increase capacity considerably at even lower speeds but they have virtually no effect at high speeds.

    johnma

    September 11, 2016 at 10:37 pm


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