Contribution
Selection of Official Reference Wind Speed for Swedish Rail Noise Calculations with Nord2000
* Presenting author
Abstract:
From 1 January 2025, Nord2000 is the recommended calculation method for railway noise in Sweden. To minimize the risk of systematic result differences compared to the predecessor (the Nordic method from 1996, NMT96) reference conditions are kept unchanged. For example, Nord2000 should simulate the refraction of NMT96, which according to anecdotal information corresponds to a wind speed of 3 m/s at 10 m above ground (in all directions).In a type case comparison, NMT96 tended to give lower results than Nord2000 at free propagation over soft ground, but higher over hard ground. In screened propagation, NMT96 tended to produce higher levels than Nord2000 for both soft and hard ground. Based on the outcome of the type cases, four real-world areas were selected for further comparisons: a city district with hard ground, a small-town centre, a residential area behind a noise barrier, and a rural area.When the areas were given equal importance, as a mean over the four, 3 m/s gave minimum differences for both equivalent and maximum levels. However, taking into account that maximum levels in rural and unscreened residential areas constitute a significant proportion of the cost for measures, 1.5 m/s was found to be a better choice.