For those who don't know / "Gauge" is the distance between the rails / and "Scale" is the proportional size of a model - in relation to the actual full size train they are modeling. So the train videos of ours that you are watching / all run on #1 gauge track / which is 45mm between the rails. But what we call G-scale / is actually made up of many different scales / that all run on #1 gauge track.But most of the trains that we run on our layout are 1:29 scale and 1:32 scale models. But 1:24 scale / 1:22.5 scale / and 1:20.3 scale trains also all run on 45mm rail track. And then there is LGB / who never tells you the scale of the trains they come out with. So it can kind of get a little confusing sometimes / trying to keep track of all the players in G scale.But here are some of the most popular manufacturer's and the scales they produce / MTH 1:32 scale / Accucraft 1:32 & 1:20.3 scales / Aristo-Craft (now defunct) 1:24 & 1:29 scales / USA Trains 1:29 scale / Bachmann 1:22.5 & 1:20.3 scales / and LGB does whatever they want to do! Hope this helps you out.Dennis