Hello RR.
I think the link to the Railway Performance Society should be included for a few reasons. Readers can see what the society is about and whether they think its references and research are worthy. Furthermore, to be frank, the RPS generally at least wants some publicity for using "their" sources and data, which, to be frank, I think is fair enough, it`s not as if they`re a business in it to make money. If you want to move the link to the reference at the bottom of the page be my guest. I think this is a classic case where an inflexible attitude to Wikipedia`s "rules" is counter productive. As I say on my "User page, we shouldn`t lose sight of why we`re actually here.

On the Cecil J Allen book, it is actually a book which I have in my collection, the full title is "Locomotive practice & Performance in the 20th Century", first published by Heffer in 1949.

On the reference thing, my eyes just glaze over when I see that, my brain is already full.... Just as I sometimes edit others grammatical errors, I`m quite happy for others to edit my references if they want !

Incidentally, is there a spelling checker on the Wikipedia software because the one on my Google toolbar doesn`t seem to work on Wiki editing for some reason.