What is the fine-grained topic of the following text: This is the fourth book in the very popular and highly acclaimed Pullman Profile series, which as with all the other titles, is a meticulously researched and beautifully presented work covering the famed Brighton Belle trains as well as the slightly less well known 'PUL' sets. Only return the topic.
Brighton Belle trains and 'PUL' sets in the Pullman Profile series book