Narrowboat Rescue on the Grand Union Canal.

Can we perform a narrowboat rescue on the Grand Union Canal? We come across a drifting narrowboat on our way towards Milton Keynes. Colin jumps off to secure the boat. Colin explains how the summit of the Grand Union Canal is supplied with water, how the 'Northern Engines' keep it moving, and we look back at the Great Train Robbery as narrowboat Silver Fox passes 'Train Robber's Bridge'.