Extreme Machines is dedicated to finding out how machines work. This program focuses on the fastest, largest, and tallest trains. We take a brief look at the steam era - at the Mallard and the huge Big Boys of the Union Pacific railways and a more detailed look at the trains of today - in particular the French TGV with its top speed of 320 mph. We investigate breaking systems, on-board computer systems and the latest in hi-tech tracks. We show some of the spectacular train crashes and disasters across time and take the audience on a time-lapse trip from London to Paris. Finally, we look at plans for the future with NASA's Maglifter concept - a launch lift for tomorrow's space train.