Is she back? or is it a one off?
I used the SRTM data extensively last year developing a program to identify set gradients for intelligent transport.
One liter of fuel passed through a small engine will provide enough energy to raise you to the height of Mount Everest.
From the top of Mt Everest a consistent 0.7% gradient will travel for over 1,000 km
Current technology, like an aero-dynamic coffin on rails, will roll down a 0.7% gradient at over 65 km/hr
That's 1,000 km/litre, or over 2,500 mpg, and the efficiency we need to be aiming for with our transport system
check it at http//www.megametrelitre.com