Meet the GER DETECT Deep Seeker: a 5-in-1 device that can detect precious metals. It can work in all kinds of trains and has a front range of up to 3000 square meters and depth of 40 meters. It has 3D imaging, magnetic metals search, and cavity detection systems.
Deep Seeker can penetrate ground layers more than other comparable devices. It has a digital compass too. You can find out more about it here.