Many thanks for sharing! Soundplan is a powerful software, but it can be very hard to learn it from scratch! Thus any tutorials are extremely helpful for a beginner. And there are not many available out there, especially for the application I am dealing with (aircraft noise)! keep it up!
The FTA FRA emissions model assumes the benefit of sound absorption from a ballasted track. Is it true that the algorithm used in the noise modeling includes a 3 dB benefit from the ballast, even though ballast does not provide adequate absorption below 500 Hz. Is that correct? In a rail system that uses a concrete slab track with rail fastened directly to the concrete, a rail silencer, can provide a broadband sound absorption capability where modular blocks are place between the rails and alongside the track. Search Nexcem and in particular the RS 200 AP model that provides 0.80 to 0.90 full octave absorption from 100 Hz to 5,000 Hz. Can Soundplan build in an option to use rail silencers where ballast is not used for rail support?
As far as I recall the FTA and FRA manual don't have any specific correction for the different ballast types. The ballast type would only effect the wheel / rail interaction and noise generation. For a lot of trains with diesel locomotives with engine and exhaust noise are a primary noise sources. FTA and FRA have not update the noise emission data for a long time.
Thank you for the reference FTA / FRA links. Unfortunately those could still trick implement I will need to check the developer that any ballast correction would only apply to the wheel rail noise and not the engine/exhaust noise for the locomotives Maybe check with in a couple week to confirm
Does the Soundplan model consider concrete slab track where rail is fastened directly to the concrete? In that case, a rail silencer would provide absorption where it would be most effective.
SoundPLAN has a number of rail noise standards implemented (~10+). Some rail modeling standards consider corrections for the noise generation based on the rail track condition (concrete, wood,...) The US FTA / FRA does not include any correction for the track conditions. In regards to the implementation of modeling manuals / standards SoundPLAN what the developer wrote or intended. For FTA / FRA modeling the user can use typical correction for track conditions defined in other standards but then they are not following the FTA/FRA manual.
Table 5-6 bottom of table: "The General and Detailed noise models are based on high-speed trains operating on ballast and track. For systems which use slab track (i.e., with direct fixation) noise levels would be approximately 3 bB higher at-grade and 5 dB higher on an aerial guideway."
Many thanks for sharing! Soundplan is a powerful software, but it can be very hard to learn it from scratch! Thus any tutorials are extremely helpful for a beginner. And there are not many available out there, especially for the application I am dealing with (aircraft noise)! keep it up!
The FTA FRA emissions model assumes the benefit of sound absorption from a ballasted track. Is it true that the algorithm used in the noise modeling includes a 3 dB benefit from the ballast, even though ballast does not provide adequate absorption below 500 Hz. Is that correct? In a rail system that uses a concrete slab track with rail fastened directly to the concrete, a rail silencer, can provide a broadband sound absorption capability where modular blocks are place between the rails and alongside the track. Search Nexcem and in particular the RS 200 AP model that provides 0.80 to 0.90 full octave absorption from 100 Hz to 5,000 Hz. Can Soundplan build in an option to use rail silencers where ballast is not used for rail support?
As far as I recall the FTA and FRA manual don't have any specific correction for the different ballast types. The ballast type would only effect the wheel / rail interaction and noise generation. For a lot of trains with diesel locomotives with engine and exhaust noise are a primary noise sources. FTA and FRA have not update the noise emission data for a long time.
Thank you for the reference FTA / FRA links. Unfortunately those could still trick implement I will need to check the developer that any ballast correction would only apply to the wheel rail noise and not the engine/exhaust noise for the locomotives Maybe check with in a couple week to confirm
Does the Soundplan model consider concrete slab track where rail is fastened directly to the concrete? In that case, a rail silencer would provide absorption where it would be most effective.
SoundPLAN has a number of rail noise standards implemented (~10+). Some rail modeling standards consider corrections for the noise generation based on the rail track condition (concrete, wood,...) The US FTA / FRA does not include any correction for the track conditions. In regards to the implementation of modeling manuals / standards SoundPLAN what the developer wrote or intended. For FTA / FRA modeling the user can use typical correction for track conditions defined in other standards but then they are not following the FTA/FRA manual.
Table 5-6 bottom of table: "The General and Detailed noise models are based on high-speed trains operating on ballast and track. For systems which use slab track (i.e., with direct fixation) noise levels would be approximately 3 bB higher at-grade and 5 dB higher on an aerial guideway."
The above note is from the Sept 2012 Guidance Manual from US DOT, FRA, High-Speed Ground Transportation Noise and Vibration Impact Assessment.