Just How many Railway stations are there in London within the M25 Orbital motorway?
Answers:
That's difficult to quantify without a little time. However, Wikipedia reliably lists the all of the railway stations in Greater London at http://en.wikipedia.org/wiki/list_of_lon. Then all of the stations in the United Kingdom are listed at http://en.wikipedia.org/wiki/category:li. These are listed alphabetically and each station's postcode is included; you can determine if the station lies within the M25 using each postcode (this will add the extra stations in the bordering counties that are not in the London list).
Hope this helps.