My Bo'Bo' (four axles) Märklin diesel locomotives:

Updated 2009-09-23

Märklin 3074, DB 216 090-1:

Märklin 3772 A, DB 212 225-7:

Märklin 3772 B, DB 212 225-7:

Bo' Bo' is actually wrong for these locomotives, as it is a B' B'.  This means that the two axels in each bogie are mechanically connected.

Märklin 3774, DB 216 127-1:

Märklin 37500, ONTC RAm 1984:

The conversions made to these models:

Märklin locomotive number		Motor		Decoder		Functions	Additional parts
		Originally fitted	Converted to	Originally fitted	Converted to/with
3074		dcm 3*	dcm 5* 6090	Analog	6090	f0 = front light, changing with direction
3772	A	lfcm 3*	dcm 5* 60904	6080 prototype	60932 mfx	f0 = front light, changing with direction f1 = interior light RH side f2 = interior light LH side f3 = driving sounds f3 = shunting speed f4 = acc/brake delay cancel f5-f15 = other sounds	456200 holder for decoder
	B	lfcm 3*	no change	6080 prototype	no change	f0 = front light, changing with direction
3774		lfcm 3*	no change	6080 prototype	no change	f0 = front light, changing with direction
37500		dcm 5*	no change	c91 sound	no change	f0 = front light change with direction f1 = interior light in the cars f2 = bell f3 = horn f4 = acc/brake delay cancel