Breuer-tractor in service at Verkstedet Kronstad. Both images are from Digital Museum from the Norsk jernbanemuseum.
See wikipedia article about Breuer-tractor (in German).

According to På Sporet 49 (page 57), there were two Breuer tractors at the Kronstad workshop. Both were built in 1955 of type 5L. Builder number 3087 was green and it service until 1985. Builder number 3095 had the later red color and was in 1985 still in service.

The Rivarossi Breuer rail tractor in the Norwegian version in its original box. It has a NEM 651 decoder socket. In front a TCS decoder that conforms to this socket.

One of the additional parts that come with the Breuer is an adapter that has the NEM 651 socket. The decoder is shown to the left.

Two little phillips screws, under the door steps, need to be removed to open the rail tractor.

The shell is now removed. At the top of the motor stack sits a little printed circuit board that needs to be removed. The adapter and decoder will take its place.

The original board is now removed (shown to the right). The adapter with decoder to the left.

The adapter with decoder is placed in the small connector on top of the motor stack. The shell can now be placed back.

Test drive, the directional head lights are working!.