Acoustic investigations on new vehicles of the Hamburger Hochbahn

Since 2012, the Hamburger Hochbahn has successively introduced the new generation of twin railcars (DT5) in its fleet. In addition to improved comfort for passengers, the new vehicles also have lower noise emissions. In order to be able to calculate this advantage mathematically in the mapping of the resulting noise exposure, the Hamburger Hochbahn has entrusted the STUVA with the processing of the procedure and carrying out metrological investigations.
According to the EU Directive on the Assessment and Management of Environmental Noise (2002/49/EC of 25 June 2002), noise mapping is required. In Germany, the "provisional calculation method for environmental noise at railway tracks of the BMVBS - VBUSch" has to be applied. For vehicles in which, due to special precautions, a further, permanent reduction in noise has been proven, the correction values ​​corresponding to the noise reduction can be additionally taken into account. As the VBUSch guideline does not specify how this proof is to be provided, the STUVA cooperated with the Hamburger Hochbahn and the "Authority for Urban Development and the Environment - Office for Immission Control and Operations (BSU)" of the Free and Hanseatic City Hamburg to coordinate a suitable procedure.
Considering the evidence already provided in 2007 by the STUVA for the generation of vehicles of the time (DT4), a reduction in the correction value could be determined on the basis of extensive sound measurements on typical track sections of the Hamburger Hochbahn for the new vehicle type DT5.
With this procedure, the proof required in VBUSch of a permanent noise reduction for the new vehicles was achieved. In addition, it was once again demonstrated for existing vehicles (DT4) that vehicles - with regular maintenance - have largely the same noise emissions over a longer period of time.
As a result, the Hamburg Department of Urban Development and the Environment set - based on the STUVA measurements and evaluations - for both types of vehicles a uniform correction value of -6 dB (A) for future calculations of noise maps based on the VBUsch. Thus, the goals pursued by the client could be fully achieved.