{
  "url": "https://openlegislation.uk/eu-decision-2002-735/annex/annex-B",
  "json_url": "https://openlegislation.uk/eu-decision-2002-735/annex/annex-B.json",
  "legislation": "eudn/2002/735",
  "legislation_title": "Commission Decision of 30 May 2002 concerning the technical specification for interoperability relating to the rolling stock subsystem of the trans-European high-speed rail system referred to in Article 6(1) of Directive 96/48/EC (notified under document number C(2002) 1952) (Text with EEA relevance) (2002/735/EC)",
  "legislation_url": "https://openlegislation.uk/eu-decision-2002-735",
  "path": "annex/annex/B",
  "kind": "appendix",
  "number": "ANNEX B",
  "heading": "MAXIMUM PRESSURE VARIATIONS IN TUNNELS",
  "text": "A significant number of tunnels (both twin and single track) exist on the certain stretches of the high-speed network that can be passed through at maximum line speed.\nWhen a train enters a tunnel, pressure waves are created in the tunnel that rebound from the tunnel ends. For health reasons, the effects of pressure waves experienced by passengers and train staff shall be limited.\nThe extent of the phenomenon depends on a number of parameters, of which the following are specific to the rolling stock:\nthe ratio between the train and tunnel cross-sections,\nthe shape of the nose of the train,\nthe coefficient of friction between the train and the air flow in the tunnel,\nthe length of the trainset,\nthe shape of the train end.\nThe aerodynamic characteristics of a trainset vis-à-vis the generation of pressure waves in a tunnel can be created from the pressure variation in the tunnel at the time of the train's total entry into the tunnel.\nThe train can be defined by an envelope curve signature unique to that provided by the three pressure variations P0, P1 and P2. An example of these values can be found on the curve below.\nPressure variation at a point within the tunnel.\nEnvelope curve unique to the trainset.\nTake these values at 250 km/h\nΔP0 < or = 1 800 Pa,\nΔP1 < or = 3 200 Pa,\nΔP1 - 0,8ΔP0 < or = ΔP2.\nThese values are given by a blocking ratio between the train and tunnel cross-sections of 0,18.",
  "extent": "E+W+S+N.I.",
  "status": null,
  "version": "current",
  "annotations": [],
  "outstanding_effects": [],
  "provenance": {
    "source": "legislation.gov.uk",
    "source_url": "https://www.legislation.gov.uk/eudn/2002/735/annex/annex/B",
    "retrieved_at": "2026-11-01T15:18:29.829862+00:00"
  },
  "licence": "Open Government Licence v3.0",
  "licence_url": "https://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/",
  "attribution": "Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives."
}