I'm not surprised, the OS only did sporadic revisions in that period and only if there were major changes. Remember that OS maps were for rating purposes, not for railway surveys.
Err, no, the OS maps are, and always have been, topographical maps (i.e. they show physical features) not for rating purposes. Railways, and changes in track layouts, were surveyed in the same way as any other change.
Having said that, it doesn't get away from the fact that many rural areas weren't surveyed between 1910 and the 1970's which is very frustrating when you are looking for a 1960's layout!
Maps received, but there's a lacuna
in Ouse Viaduct/Balcombe/Lewes project
A blog by 10800 in RMweb Blogs
Posted
Err, no, the OS maps are, and always have been, topographical maps (i.e. they show physical features) not for rating purposes. Railways, and changes in track layouts, were surveyed in the same way as any other change.
Having said that, it doesn't get away from the fact that many rural areas weren't surveyed between 1910 and the 1970's which is very frustrating when you are looking for a 1960's layout!
Wrong end of the country, but see here http://www.rcahms.gov.uk/the-national-collection-of-aerial-photography1.html for some aerial photos in Scotland.