Hi,
I hope this post isn't unwelcome, but since members of Great Western Passengers' Forum clearly enjoyed reading the Railtrack Letters, I suspect you'll appreciate this.
Since the original PDF was published, over 100 new letters have been received - and replied to.
The book, Railtrack and Other Letters has been published as an eBook for Kindle: http://www.amazon.co.uk/dp/B00CMCCHOG/
... and as a paperback: http://www.lulu.com/shop/john-hein/railtrack-and-other-letters/paperback/product-21005525.html