This article deals with the Eastern Region of British Rail, but presumably things would be similar in the Midlands, so may be of interest
journal.sciencemuseum.ac.uk

How Britain’s railways prepared for nuclear war - Science Museum Group Journal
From the late 1940s until the mid-1960s, Britain’s railways planned and prepared for a possible nuclear war. While hampered by a lack of government funding and guidance, they nonetheless endeavoured in the hope of repairing and rebuilding after nuclear Armageddon.
