Hail All!
Sorry I took a while to get back to this...Keep getting diverted to other forums, websites I gotta build etc - I really need another three of me around here to do the work I keep setting for myself!

hock:
Death,
Just a casual wave at waist or slightly higher level would work whilst keeping the rest of you well behind that line would be normal. A hand raised outstretched head height would make you look like an off duty rail worker so ok as well I guess.
Cheers for the info, GhostCav...I'll stick to using the normal "car drivers" wave then.
Oh & don't wear red as pointed out before (or green/yellow for that matter, especially wearing green & swaying from side to side, that would really shock an older driver with its meaning). But then again I'm taking you for more of a black wearer to be honest.
Aye, I generally wear Black as ye rightly guessed...Although - Being a man who feels at home within the deep forests of ancient Albion - I am also known to wear Elven/Heritage/Camoflage green a lot of the time as well.
May I ask what that Green/Yellow/Swaying signal would be interpereted as? Sounds like a rather odd-ball event or conditions being indicated if it requires a signal like that!
Try standing 4 feet away from a Freightliner doing 75mph with a long and fully loaded train
I've stood about 4-6' (Still behind the yellow line) from a 442 passing a platform at 90mph, and - Though I didn't feel in any danger doing so (Else Id've stepped back immediateley) I could feel a slight drop in pressure and a very slight "tugging" force closer to the train. I wonder what the turbulance would be like in the case of an APT passing a platform at it's optimum 450mph?
Nowhere runs at 140mph. The CTRL services will, but I expect they will be stopping at every station along the route while the non-stopping Eurostars will be kept at a safe distance on the fast lines.
Hang on a second...I always had the 91's down as capable of hauling a whole IC-225 along at a good 145mph or so, and I've also had 140mph down as the normal operating speed on the ECML...To say nothing of
standard 140mph operation down the Trent Valley lines!

hock:
Given that an IC-225 with two 91's on it (As opposed to the usual 91+NMDT combo) would happily manage 210mph in normal operation, if they're not running those things at their full BR-designed potential, is it any wonder it still takes us a whopping
FIVE HOURS to reach Edinburgh from London? :roll:

ad:
I personally wouldn't recommend getting that close to a non-stopping service. What if you lost your footing or slipped on something on the platform? I don't entirely believe that people can be sucked off platforms by non-stopping services, but I wouldn't take the risk myself. Trains do create a lot of turbulence.
Whilst writing my response to the above about the dangers of turbulance, I had the following thought enter my mind on the subject, given what I know about air pressure as it relates to aircraft...
I've just realised that the drop in pressure caused by a passing train plus the higher pressure from the surrounding area would cause air-flow to head into the train itself...And if the speed of the train was sufficient, then anyone entering the vacuum thus produced would actually be putting themselves at risk of being pulled into the passing train - Especially so if (Does a quick mental calculation) the train in question is travelling faster than 175mph! 
hock:
Are my thoughts on that correct, or have I made a technical førk-up somewhere?
Drivers will react differently. I personally hate having people over the yellow line and will whistle at any that haven't already moved back as I start my run through. There's nothing much I can do if they don't move back even after that, but it doesn't make me feel any happier. I'd rather you weren't standing in the "suicide spot" at all.
I had thought of that initially, as the only thing that would be suggested to a rapidly approaching driver if a person didn't move out of the way on approach would be that s/he might jump...Hence my suggestion of moving in after the front of the train had passed, so that I'd still be behind the line on approach, and the driver wouldn't think that I was going to try and buy myself a Cheap Single to Utgard!
Farewell...
>> Death <<