On Thu, Mar 19, 2009 at 06:38:09AM +0000, Neil Williams wrote:

A more clever system could use the GPS data to derive how far the
train travels on one revolution on that day and use it later when the
GPS was not available.

You're buggered if there's the wrong type of leaves on the line though,
cos then rotations has only an approximate correspondence with distance
travelled.

--
David Cantrell | Cake Smuggler Extraordinaire

In this episode, R2 and Luke weld the doors shut on their X-Wing,
and Chewbacca discovers that his Ewok girlfriend is really just a
Womble with its nose chopped off.