[troutmask]

A folding bike...
I use a Dahon Speed TR. As I carry a load of photography gear when I go cycle camping I have panniers front and rear. I take them off, fold the bike and put it in a luggage rack.
Just come back from a week in Wales and it always works. The train people sometimes get a bit fed up with waiting for me to load all the stuff on, but they havn't been able to say "we already have one bike on here so you can't put another on" as as happened in the past.
Many companies state that you should book your bike in advance (which is often impossible, see last weeks "Private Eye"), but this dosen't apply to folders.