Stenlake Publishing do an extensive series of nostalgia books. I discovered these when at home four years ago while researching our towns old railway station. Most of the books are collections of old photographs of towns in days gone by but there is a large series which covers the last days of steam in the 50's and 60's, and also lost railways which charts various railway lines before they fell under the axe. More than half of the range is about places in Scotland but there are plenty of places covered in England, Ireland and Wales too. They provide good photographs of many stations, trains and railway lines of which there is no trace today.
I have bought quite a lot of these books and intend to buy more. I suppose because I am living overseas at the moment I tend to be more nostalgic than most but of you are trying to model a branch line which no longer exists then these are certainly worth a shot. They have other series which cover canals and shipping, mining, aviation and road transport, football and golf. They can be bought from many high street shops, Amazon or direct from the publisher (which I would recommend as they give you your fourth book for four quid).
If you are wondering what the strange Zeppelin thing is on the cover of the Glasgow book, it was a precursor to the monorail.