[paddylucas]

Hi

I regularly commute from Bedford to Woburn Sands along the MVL. Each time the train (Class 150 or Class 153) departs from Bedford St. Johns there is a loud hissing sound. I am at a loss as to what it is. Moreover, this "hissing" does not occur around other stations along the line. Any ideas as to what this is?

Regards

Patrick