Here are three sets of photos from Alan Ng, Thomas Hartwig (www.panzer-modell.de) and Michael Shackleton.
The training of drivers for a modern main battle tank requires a large amount of resources. Most driver training is done in the classroom and on simulators. However, there is no substitute for the real thing. Lack of space in the driving compartment of an actual tank led to the development of a driver training tank.
In place of the turret, these vehicles were equipped with an instruction cab with sufficient space for two observing trainees seated either side of the instructor. To maintain the characteristics of the original vehicle, the turret weight was compensated for by an 8.5 tonne ballast weight. A dummy gun is attached to the front of the cabin to increase realism for the driver (though these were not fitted initially). The original Bundeswehr trainers also did not have air-conditioning. The instructor has a system which makes it possible to override the driver under instruction (seated in his normal hull position) when necessary. Most Fahrschulpanzers have their rear intercom boxes and most of the tools removed, as illustrated here with a cab on a 1A5 hull.
Similar vehicles have been used in other armies such as Australia, Belgium, Brazil, Canada, Denmark, Greece, Italy, Netherlands and Norway. All are slightly different in their equipment. For example some have dummy guns, some don~t. Likewise with air-conditioning units, which can also vary from country to country. The non-German tank hulls used with the cabs sometimes retain all of the tool clips on the hull sides (though the tools are normally removed) or hull boxes if the MBT is equipped with them.