Question to the Department for Transport:

To ask Her Majesty's Government whether HS2 Ltd's Noise Prediction Model is more accurate than the Noise Prediction Model developed for HS1; and how this can be demonstrated.

High Speed 2 is currently using the prediction model originally developed for HS1 to predict noise from the operational railway. Input assumptions have of course been varied to reflect relevant differences, such as the higher speeds of HS2. As set out in the Environmental Statements for Phase 1 and Phase 2a of HS2, this prediction method has been shown to generate noise predictions that agreed well with actual measurements taken of high speed trains in France.

The hybrid Bill process intensively scrutinised how the HS1 noise model should be applied to HS2, and which input assumptions should be used. Where those input assumptions are further refined during the detailed design stage, for example as the performance of the track or rolling stock is refined/confirmed, the new assumptions and their evidence base is shared with local authorities through the relevant HS2 Planning Forum subgroup.