Railway Model

The PEN3D Railway Model is an implementation of the environmental noise model. 

The model calculates the Leq and Lmax from rail object.

The  contribution Leq(1 hour) from each segment is determined by:

       Leq =  Lw  - 10 log10(4π d2 + 2 π d L) + AE + 10 log (T /3600)

where:

       Leq =        the Leq sound pressure level at an observer

       Lw =        the sound power level of the source

       10 log10(4π d2 + 2 π d L)  is the Distance attenuation

       AE is the excess attenuation factors and is determined as the sum of the contributions

       T =        Time to traverse the segment (s)

       L =        length of vehicle in (m)

       d =        distance in (m)

The  Lmax from each segment is determined by:

       Lmax =  Lw  - 10 log10(4π d2 + 2 π d L) + AE

The overall Lmax is determined by the maximum of each segment.  The user determines the angle of segment with 10 degrees being the default setting. 

Although termed a railway model it is in reality a moving line/point source model.  Therefore it is applicable to modeling vehicles in car parks, trucks moving on haul roads and numerous other similar sources.  Simply set the length of the "line" to be equal to the dimensions of the moving source. 

The PEN3D software was originally developed in 1993 and has been in constant development and refinement. 

All Point and Batch calculations in PEN3D Railway model are free-field i.e. do not include the +2.5 dB(A) facade correction.

Refer to the environmental model for calculation of the excess attenuation factors.