Thanks. My old sat nav sometimes took a while to get a fix, and it had a screen that showed you where in the sky the satellites where and a dynamic bar graph like a audio graphic equaliser, that showed you how many sats and how strong the signal was. You could watch it and it would have a clear view of the sky, have anything between 8 and 12 satellites, all with signals over 50%, but it would still take two minutes or so to decide where it was.
I've often watched it thinking, and so if you can see all that, why can't you tell me where I am?
My car on the other hand has a built in sat nav, with an external GPS receiver and I've never know it to loose signal other than in a tunnel, and it is usually operational before I've pulled off my driveway.
The train was one of these
http://en.wikipedia.org/wiki/British_Rail_Class_222 East Midlands St Pancras to Kettering. It is impossible to hold a telephone conversation on that route, but I have followed the train's route on the phone using GPS before. I'm one of those geeky people interested in Geography, when on a train or plane, I like to know what I'm looking at.