If you travel by train you will see man made objects by the line side throughout the journey, including railway signals, signage, infrastructure, fences etc. You will find their model equivalents listed here
Adding lineside detail gives your model railway layout added realism and interest, it also provides an enjoyable way to continue enhancing your railway long after all the track has been laid.
You can find out more about the different scales and gauges in our article: Model Railway Scales + Gauges Explained: All you need to know