Among the Western world's narrow gauge railways, the thirteen-mile long Ffestiniog in North Wales stands supreme. Its history, engineering, locomotives, carriages, all in its magnificent mountain setting, together make this one of the country's top tourist destinations.

But this same remarkable railway was once a world showpiece in a previous incarnation. Well over a century ago, engineers from around the globe came to North Wales to study how British ingenuity was bringing trainloads of slate from the rugged mountains of Snowdonia, to serve the building trade worldwide. Yet between those great years and today lay another age - an age of bankruptcy, rack-and-ruin and bramble-choked desolation. Worst of all, nearly two miles of track vanished under a man-made lake.

Yet the appeal of this line was such that, over a span of some thirty years, volunteer workers young and old, from all walks of life, banded together to dig the railway out of oblivion and hew a new line through the mountains to by-pass that man-made lake. Other railways, and canals, have been rescued since; but the scale and effort of the Ffestiniog story remains quite unmatched anywhere else.

This second of two programmes, again using extensive unpublished archive footage, allows a rare behind-the-scenes insight into the motivation and methods of those who became known as the 'Deviationists'. Through hard work and determination, this handy band of optimists rebuilt their unique railway all the way back to its old terminus at Blaenau Ffestiniog. And thanks to the camera-work of Dr Brian Rogers and others, we have a moving picture record of how, against all odds, a veritable mountain of bureaucratic and practical challenges was overcome. Many warned it couldn't be done; but it was - and his video shows us how.