Hi all,
I didn't see the doco (yet), but I'm guessing they weren't implying that the train actually reached 100% light speed (impossible according to relativity, and 99% of scientists). To get a time dilation of 1 week = 100 years (a factor of 1:5200) requires a speed of about 0.99999998 the speed of light. (from
http://www.1728.com/reltivty.htm)
I'm very rusty on relativity, so this may all be rubbish, but ...
I believe a key point with the fuel consumption is that the mass of the train, (and the fuel) appear to be different depending on your frame of reference, also the distances traveled appear different depending on the location of the observer.
The observer on the train would see the mass of the train increased by a factor of 5200, also the distance (and the earths circumference) would appear to _contract_ for those on the train by the same factor. In the end all of numbers should balance out, so that 1 weeks travel at 1/5200th the distance does the same number of laps of the earth as seen by the earth observer over 100 years.
Those on the train find that fuel consumption has gone up to billy-o because their mass has increased. so they use up their 100 years worth of juice in one week! (I'm still missing something here? the fuel weight went up by the same factor ??)
So in short, my guess is 100 years worth of fuel needs to be put on the train.