In this article Tim Lomas discusses one of the best resourced themes you can find: your local railway.

Railways make one of the best themes for a historical study. No place has ever been far from a railway station even if Dr Beeching wiped out one-third of the network in the 1960s. Few places of any  size, and indeed often of no real size, lacked a railway station. Railways often have a fascination for those of all ages. For children Thomas the Tank Engine is  probably among the most famous, but  there are many others. So much fiction has trains as a central theme whether mysteries, murders or romances. One can easily visit or investigate a railway either as a modern mode of transport or on one of the many heritage railways,  and even long-lost lines can often be traced in part on the ground. Even when not possible, the website and other sources yield an incredible number of old films and websites such as ‘Disused Stations’  (at the last count well over 2,000 of them) as well as masses of YouTube films which enable much of British railway history to be traced...