G Gauge is a model railway scale that typically has a ratio of 1:22.5, meaning that one unit on the model represents 22.5 units in real life. This scale is popular for outdoor garden railways due to its larger size, which allows for more detailed models and better visibility in outdoor settings. G Gauge trains can run on tracks that are 45mm wide, making them compatible with various types of rolling stock and accessories. This scale is often used to model European and American trains, providing enthusiasts with a versatile option for creating realistic layouts in gardens or large indoor spaces.