Hello Hess
The 3016 Märklin railcar from 1960 to 1976 (Box color) has an SFCM (Small Flat Inductor Motor).
One bulb at each extremity which are meant to be on all the time
1 Motor unchanged, simple decoder
So either you use a decoder for AC motor (Märklin 60906) without changing anything to the motor. The decoder simply replaces the direction relay.

2 Motor replacement (Märklin 60943) and mLD3 decoder (Märklin 60982)
In this solution the motor is replaced with a 5 pole DC motor and the mLD3 decoder has the best regulation and speed control of all solutions

3 Inductor Replacement (ESU 51961) and mLD3 decoder (Märklin 60982)
In this solution, only the coiled inductor is replaced by a magnet inductor and the mLD3 decoder has the medium regulation and speed control of all solutions

Notes
- all 3 solutions have MFX, DCC and MM2 capability
- solution 1 has no motor regulation It behaves like an analogue machine (slows down uphill, accelerates downhill). Cheapest of all solutions
- solution 2 is the best solution: excellent regulation, 5 pole motor
- solution 3 is the medium solution: good decoder but same old 3 pole motor and good regulation Cheaper than solution 2.
- all solution include the cabled version of decoder because the space inside the unit is limited
- in theory, an mSD3 decoder could be used but this adds a lot to the cost and the sometime noisy machine does not deserve a sound decoder
- please verify my assumption about the motor type is correct (SFCM) as later models (with other box design) have a DCM (Drum Collector motor) which call for a different Märklin motor (60941) or a different ESU magnet (51962)

Cheers
Jean

thanks jean it was a cheap bus so will go with Märklin 60906 this will be my first conversion so keep it simple i have put the bus on my step layout just to see it run i really like how it struggles up hill flowed buy a Wight knuckle scud ride going down if it was a loco then I would change the motor as for the light bulb's they light up and shine through the plastic shell and make the opaque glass look really bad so will be removed

hess

Hi Bill, I have used the 60972 decoder in 3 locos so far and I haven’t found any problem. Having said that I never used the 72442 module so I can’t comment if the decoder handles the module. My plan is to use the CS3 events (or may be another software in the future) to handle slow downs/breaks. Denis