This collection is a review of the extensive network of narrow-gauge railways, the popular "carrilets", that existed in Catalonia.
It is divided into 20 volumes that review each line of this network. It contains the description of their history, their technical and operational characteristics, their stations and installations, the natural features and the towns they go through, as well as the locomotives and the rolling stock that served them.
Each book offers, in the same way, a complete description of the current state of each line, station and the preserved locomotives and rolling stock, as well as additional economic, statistical and social data.