I deal with about one a week on average in the bmi forum, and if you add together the various threads from the destination forums and the airport forums you'd get a handful more (including a huge chunk of dicussion in the Destinations>Europe>London forum). I guess people might start more threads if there was a more obvious 'home'.

Actually these links above prove my point. Most of them don't provide anything like the degree of knowledge and experienced-traveller input that you get here on FT...they are the rail equivalent of airliners.net. The brilliance of Flyertalk is that it tackles the consumer end for flyers - the reality of flying, how to get the best deals and how to maximise points and miles. These are the kind of issues that a rail forum within Flyertalk would be able to discuss: how to use rail travel in conjuction with air travel, how to go about ticketing in various countries, what services have the best on-board food etc. Besides, Flyertalk is deservedly popular; the first link goes to a site with nine posts in two years

Given that FTers have enormous accumulated wisdom about hotels, car hire and restaurants, I don't see why rail travel can't be given a place of its own.