die belebende Bedenkung

A trip aboard HS2

with 2 comments

HS2 step at platform, diagram

On 20 April an OJEU tender notice was issued for the ‘£2.75 billion, 60-train’ HS2 phase one rolling stock procurement. HS2 Ltd’s Pre-Qualification Technical Summary states its intention to procure “a single fleet of rolling stock that will be capable of operating on the HS2Network and the Conventional Rail Network (CRN), referred to as the ‘Conventional Compatible’ or ‘CC’ fleet”.

A perusal of the PQTS seems to confirm the view that the rolling stock specifications are as muddled as the rest of the project, but HS2 Ltd do not intend to change them in any substantive way.

[HS2 Ltd]

This PQTS is a precursor to the full Train Technical Specification (TTS) which will be provided with the Invitation to Tender. The requirements of this PQTS will be incorporated into the TTS along with other more detailed performance and functional requirements. Note that the TTS will supersede and replace the PQTS. HS2 Ltd does not intend to change in any substantive way the requirements set out in this PQTS. However, HS2 Ltd reserves its right to do so and will identify any such changes in the TTS in due course.

Contrary to all the accessibility hype, the PQTS suggests that there is little to no intention to provide ‘step free access’ between all stations served by HS2 trains. Even on the handful of stations on the captive network (“HS2 Platforms”), ‘step free’ access would involve negotiating, er, steps.

[HS2 Ltd]
The maximum vertical step between the deployed Moveable Step and an HS2 Platform shall be +20/-0mm except under Exceptional PTI Conditions.
Rationale: The maximum single step negotiable, unaided, by 98% of wheelchair users is +20mm; higher steps are negotiable but with decreasing success rates.

[…] The maximum vertical step between the deployed Moveable Step and an HS2 Platform shall be +30/-10mm under all conditions including Exceptional PTI Conditions. The TMM and HS2 will agree the Exceptional PTI Conditions, which are expected to include rarely-experienced vehicle conditions such as deflated suspension or Exceptional Payload.

[…] The maximum horizontal gap between the deployed Moveable Step and an HS2 Platform shall be 30mm.

[…] When deployed, the Moveable Step shall have a minimum horizontal surface depth (perpendicular to the bodyside) of 240mm

[…] The maximum vertical distance between the Moveable Step and the floor of the vestibule shall be 30mm.

Wouldn’t vertical discontinuities of those sizes, on a pavement of the public highway, be considered as “trip hazards”?

Does the claim of HS2 'step free access' match the reality?

Does the claim of HS2 ‘step free access’ match the reality?

The technical standards which HS2 is being designed to are obsolescent and inappropriate. For example, the train crashworthiness is based on a low-speed ‘level crossing’ collision with a heavy goods vehicle (which would be much lighter than the train), yet there would be no level crossings on HS2.

Survivability in realistic crash scenarios at actual HS2 operating speeds, is not considered at all.



Written by beleben

April 23, 2017 at 5:50 pm

2 Responses

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  1. It is not clear why HS2 are proposing 1115mm platfoms. Various HS2 / DfT pitches to the EU since 2013 have stated that a platform height of c.1200mm is necessary to achieve step-free access with existing very high speed trains having distributed traction. The floor height over the bogies is around 1250mm. The trains needed to meet the HS2 service specification with any degree of reliably will almost certainly require more power and better brakes than any existing train. Whether the manufacturers can cram everything into a train body that can fit within the UK loading gauge remains to be seen.

    If the maximum vertical distance between the moveable step and the vestibule floor can be 30mm then it would seem that an unspecified number of wheelchair users will fail. HS2 have acknowledged that the average passenger weight should be 90kg (with baggage), which is10kg higher than the EU standard. They do not seem to be allowing for an increasing proportion of mobility impaired people.

    The spec says is that “Bidders should assume that legal requirements allowing the use of platforms at such a height will be in place prior to the HS2 network being brought into service.” This suggests that the EU TSI requirement for 760mm platforms has been discounted. It would therefore be very sensible to look at all the other TSI requirements that have little or no value but impose extremely high costs to this and other schemes.


    April 23, 2017 at 8:43 pm

  2. It seems possible that the choice of an 1115mm platform height is so that there is sufficient clearance to allow an extending step, which can fit under the train floor, to be above the platform. If the new HS2 platforms were built much closer to the track, as would be possible if all the trains were designed to normal UK standards, then there would be no need to use an extending step at such stations. In that case the platforms could be built higher to give truly step free access. Extending steps could still be deployed at existing stations with lower platforms although many people would find the c.300mm difference in height between the platform and the train a barrier. The PQTS has some onerous requirements for reliability and it seems that the need for an extending step to be deployed on each door at every station is another potential failure risk. So what are the additional costs of constructing HS2 to take EU size trains, none of which are being sought for Phase One? What connectivity and operational benefits would there be if high speed trains could go into and through existing city centre stations rather than having to reverse in termini?


    May 6, 2017 at 11:28 am

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