NLS on line OS Maps

On line National Library of Scotland OS maps now have 89800 maps covering England & Wales at 25 inches to the mile, which provide tremendous detail.   There are 3 series of 25" OS maps for the NE of England, dated around 1895, 1914 and 1939.

Andrewshouse Colliery from a 1914 25" OS map - note signal posts, garden sheds, netties, etc
Track details are interesting - eg Marley Hill shed is connected to the Andrewshouse branch
(Reproduced with the permission of the National Library of Scotland)

The NLS are providing a tremendous free service to historians and interested parties across the whole UK in publishing OS maps, and continue to increase coverage & enhance functionality.