Only ones starting from London "because Not Work rail and the Authorities have Crowd Control Plans in place that Cannot Accomodate Extra Numbers of Passengers" or some such drivel, according to what I saw in one of the Magazines. It won't make any difference anywhere else, e.g. the Settle & Carlisle and so on. Not Work Rail did say that tour oeprators wouldn't be able to run to Weymouth during the Olympic 2012 Sailing Events on account of "all the extra trains that will be running", but that of course is a lie because there's only one or two Xc services that will be extended to Weymouth.
Once again, of course, it's the Government treating everyone who doesn't want to flock to the Capital for the Festival of Running and Throwing Things with complete and utter indifference, because how dare they not want to flock to the Festival of Running and Throwing Things? Damn unpatriotic, not wanting to give money to the London Organising Committee for the Olympic Games. It's the most important thing that's ever happened, and everything else must be sacrificed to make way for it.