Whilst at the K & WVR autumn gala I was viewing Howath shed yard from the public viewing area, and I could hear a strange noise, sort of like a drunk duck quacking and passing wind.
Later, I went on an official guided tour of the shed, and I asked the guide about the noise. He said it was their "new" 08 shunter, and they all did it in some form or other.
I got to ask one of the fitters, and he said it emanated from the automatic drain valves on the air reservoirs. These allow water in the system to be automatically ejected.
Seems as the pressure gets lower the noises get more prominent.
