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Financed by:
  • Deutsche Gesetzliche Unfallversicherung e. V. (DGUV)
Research institution(s):
  • Müller-BBM GmBH, Planegg
Type of hazard:



noise, personal protective equipment

Description, key words:

warning signals, hearing protection, engine driver/shunters

Development of a measurement method regarding audibility of warning signals for engine driver/shunters impaired by hearing protection

Project No. FF-FP0355




With the implementation of the new ordinance on noise and vibration protection, the values for prevention have been decreased. Engine drivers/shunters work partly under strong and threshold exceeding noise. The importance of audibility of warning signals causes, that hearing protection is not always used by every engine driver/shunter. There is a mathematical method to sort the hearing protection in different groups with different tolerances. In addition to the mathematic procedure, it is necessary to perform an individual hearing test according to BGI/GUV-I 5147 to guarantee the adequate perception of the signals. This investigation shall be added to the existing procedure which is very time consuming and complex. The purpose of this investigation is to make sure, that warning signals are not impaired by hearing protection. The hearing test shall be done in a room with normal acoustical conditions where the situation on the rail and loco shall be adopted as realistically as possible.


To perform the hearing test under most realistic conditions in a normal room, all relevant acoustic signals (warning and interfering signals) need to be recorded on the rail with head-based measurement equipment. The test signals are evaluated binaurally by the engine driver/shunter. A 2AFC (two alternative forced choice) method is used for the panel test. The developed software detects the masked threshold of the test person by classification of their answers. At the end of the investigation, a panel of engine drivers/shunters shall perform the test according to BGI/GUV-I 5147 as well as the new hearing test. Therefore, both results can be matched and the new method can be validated.

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