Ian Tindale wrote in message ...
Boltar wrote:

Pressurised air in the brake pipes or tanks moving about?
Sound of the brake pads on rubbing on the discs?
Anything else that can produce a kind of white noise sound really

That's a completely different kind of sound to that described in the
subject.

Not necessarily , plenty of streams sound just like white noise and so does
water coming out of a tap very fast.

B2003