This is № 457 of Pilentum's model railroad videos. This model railway layout is more than 20 years old and has a total length of 50 meters arranged over three modules. The model railway was built with Märklin tracks in HO scale.
This is № 419 of Pilentum's model railroad videos. Building model railway layouts is an international hobby. So even in Rome, Italy, there is a model train club, called “Gruppo Fermodellistico Tartaruga”, whose members are constructing a large modular model railway in HO scale.
This is № 411 of Pilentum's model railroad videos. How to build a small model railroad layout in HO scale? Carlo Viganò has solved this model railroading question with his dreamlike layout, which is called Plastico Ferroviario Vallecasanuova.