Thanks for sorting that out. That is way lower than I had expected. So that was from a trackside position with them during a normal drive by. I was remembering when we drove Graham's in the industrial area. That was really loud. I seems we were getting the amplified effects of the reflected sound there. Ofcourse the open space would always dissipate the sound better but 37 is a good figure.
No extra silencers needed i would say. One thing to tick off the list.