During our week in London, we stayed in a vacation apartment just a little southeast of the city proper in Lewisham (Grove Park), across the street from the home of author Edith Nesbit, who wrote The Railway Children, Five Children and It, and many other books for children. Our apartment had a DVD copy of the 2000 movie adaptation of The Railway Children, so of course we watched it. It seems like I might have read the book when I was young, but I don't remember it at all. We enjoyed the movie very much, especially because it was filmed in lovely Yorkshire, which we had just left.
I liked the movie enough that I found a free, public domain copy of it for Kindle and read it on my phone right after we saw the movie. (I don't have a Kindle, but I use the Kindle app on my phone quite often. I'd prefer to use Google's Play Books, but it has been hard-crashing my phone lately, and who needs that?) I like the book even more than the movie, which is to be expected, I guess. Nesbit tells the story mostly from the points of view of the children. Her writing is pleasant and has a gentle humor that I loved.
The Railway Children is the story of three children who must suddenly move to Yorkshire (from London, I think) with their mother after their father mysteriously disappears -- mysterious to the children, though not to the mother, and all is explained later in the story. The children learn to love the railway that passes near their home, make friends with all the locals, get into small scrapes, and also go about helping people in various ways. Their adventures are sweet, sometimes serious, and always entertaining. It's great to read an interesting story about nice people.
There's also a 1970 film that I haven't seen but would like to. We have a copy of the movie adaption of Five Children and It (2004) that I remember enjoying, but I haven't read that book. Probably should, though.