Basically, there are two methods to build a model railway layout. On the hand a model railway layout can be built on a single plate. In this case width and length finally define the size of the whole layout. On the other hand single modules are built by members of a model railway club. Because of consistent standards in module construction, wiring, DCC, track and scenery, these single modules can be fitted to a very large modular model railway. For example, FREMO, Free-Mo, Mod-U-Trak and Modutrak are well known standards for building those model railway modules.
In this video Pilentum presents a model train cab ride along a very large modular model railway layout. There are more than 50 meters of HO scale railway tracks in narrow gauge. The whole model railroad layout presents the famous Furka Cogwheel Steam Railway in Switzerland. This Swiss mountain metre gauge railway operates between the Realp railway station in the Canton of Uri and the Oberwald railway station in the Canton of Valais, crossing the Gletsch railway station also in the Canton of Valais. Because the entrance of the tunnels were built so low, what is usual for narrow gauge railways, Pilentum's cab ride camera does not fit. So Pilentum had to make a video cut between the tunnels.