Minitrix’s little control coach had changing rear lights

At the bottom of page 21 of the 1975/76 Minitrix catalogue, the silver driving trailer has a detail that is easy to miss: its lights change with the direction of travel.

No. 3040 is described as a BDnf coach with a driving cab and lighting. The small yellow lamp symbol beside it marks a working feature, rather than another printed detail on the body. The catalogue gives the model a length of 165 mm.

Above the coaches, Minitrix also illustrates its separate interior-lighting set, no. 6641. The drawing shows the contacts and lighting strip outside the coach, and the text describes it as a simple fitting.

For anyone restoring an older N-gauge passenger train, those little catalogue symbols can be as useful as the photographs. Has anyone kept a 3040 running with its original lighting?