It is often a nuisance for residents living near railroad lines - and such a multi-faceted challenge for experts that there should be more than one word for "railroad noise". Sounds from steel wheels on rough or smoother rails, braking sounds at different frequencies, engine noise, aerodynamic noise... - all of it muffled or influenced by noise barriers, embankments, the nature of the ground beneath the tracks, and by the environment in which the sound waves propagate.
researchers led by Reto Pieren from the Laboratory for Acoustics / Noise Control know from practical and theoretical experience just how complex these acoustic consequences of rail traffic are. For years, they have been exploring the phenomenon with measurements, simulations, validations: Findings that led to the two-year EU project SILVARSTAR with many partners (see infobox). Now Pieren presented the results at the "forum acusticum" conference in Turin: an acoustic simulation of various types of railroad noise - audible and tangible with the help of virtual reality.
Many factors, even more variationsThe ultimate goal was a tool that even laypersons could use. For example, transport politicians who want to assess the impact of a future railroad line. How they experience such virtual drive-bys is exemplified by a ( For a single line, several scenarios can be compared, for example with train types ranging from cargo trains to a regional train to an ICE, with high or low noise barriers, specific wheel and damping types that also have an audible impact on railroad noise, and many other factors. And because the environment also plays a role, users can decide between "city" or "countryside" or even select a ground-level or elevated position, such as on a balcony.
Comparison of noise scenarios in a video:
Positive reactions at the demonstrationsBut the effort is worth it, as the validation of the system showed. The graphs of the synthesized noise curves are very close to measured real-world values and are even partly congruent. Subjective impressions were provided by demonstrations at transport technology trade fairs such as last year’s InnoTrans in Berlin: Visitors attested to the simulation’s high credibility and showed great interest in using the virtual "rail noise game".
For those interested, the tools, including a license agreement for non-commercial purposes, can be downloaded from Empa’s SILVARSTAR website. "The first uses of the simulation are already starting," says Empa researcher Pieren, "we are very satisfied with the results and expect numerous applications in the future."