Digital Conversion Options
The Train Doctor


Digital Conversions


Mechanical:     To get good results with a digital conversion, it is essential that the locomotive be mechanically sound and in good running condition.  Fitting a decoder and high performance motor into a badly running unit will not fix problems caused through “bad mechanics”.

Whenever I undertake a digital conversion then, I will normally give the loco a thorough mechanical inspection and service, and replace any worn parts (gears etc) as part of that exercise.  I will not "slap a decoder" into a locomotive 


In some locomotives it may be necessary to modify the loco chassis or shell to enable the fitting of the high performance motor parts, a speaker, or the decoder itself.  Understandably there may be some reluctance to have this done, so if it proves necessary I will always discuss it with you before commencing the work. 



Motor Options


With the exception of Delta decoders, most modern decoders require a motor with a permanent magnetic field in order to get feedback to the decoder for load regulation purposes. For locos equipped with one of the standard Märklin universal motors, the normal method of achieving this is to convert that motor to a DC motor with a permanent magnet. There are 2 options to achieve this: 


Motor Option 1.  Replace field coil with a Hamo type permanent magnet – The original armature and brush plate are retained.  Advantage:- cheaper.  Disadvantage:- motor is less powerful (Weaker magnet, bigger armature field magnet gap) and less smooth (3 pole motor). Also, when converted in this manner the early “flat commutator” type motors can exhibit intermittent speed characteristics between certain speed steps, due to "brush bounce" on the commutator. (e.g. a sudden speed surge between speed steps 6 and 7).  The Preiserlings aren't very fond of this at all.


Motor Option 2.  Replace the whole motor assembly with a Märklin high performance drum commutator motor. This is a more expensive option but has the advantage over option 1 of being more powerful (better magnet, finer mechanical tolerances); and smoother (5 pole motor).   Also the drum commutator doesn’t suffer from the brush bounce problem as in option 1.


Locos equipped with Faulhaber or coreless motors, or other "canned" DC motors  are usually converted to digital without any motor modifications.





Decoder Options


Delta Decoders are the “bottom end” of the digital range, and can be fitted directly to a Marklin universal brush type motor without any motor modification.  Performance is poor in digital mode (generally not as good as the loco before it was converted) and these decoders have no load control, no simulated inertia, often give noisy performance especially at low speed, and suffer from rather coarse speed control.  Retro-fitting with this type of decoder is not generally advised except in special circumstances where it may be undesirable or impossible to fit a permanent magnet, and therein lies the one advantage of Delta Decoders: Because there is no permanent magnetic field in the motor to "grab" the armature when power is removed, Delta equipped locos will tend to "coast" better than permanent magnet locos over dirty spots in the track or other places where power pick-up may be momentarily interrupted.  The lack of simulated inertia is also less of a problem when using a CS2 controller as the various iterations of this unit can apply their own simulated inertia by issuing a series of "slow down" or speed up" commands (to put it in very basic terms)


Depending on the particular Delta decoder, up to 80 addresses are available, and up to 27 speed steps.   Earlier Delta decoders have only 15 selectable addresses as they came from the factory, although it is possible to modify the addressing lines to obtain 80 addresses.


Märklin 60942, 60962  MFX/DCC/Motorola Decoders:        Updated Jan '12

This is the long awaited new decoder from Märklin now finally released for retrofitting.  I have had a bit of a "play" with these, and believe that they have some advantages over the ESU lokpilot & M4 (MFX) decoders that have been standard fare for so long.  It is early days yet, and I haven't yet tested the "sound" version, but certainly what I've seen so far looks good.  Presuming they stand up to some further testing I'd like to do, I will be carrying these in reasonable quantity.

They cater for MFX, DCC, and Motorola protocols all in the one decoder, and price-wise work out about the same as the lokpilot.


There is a short report on my testing at the bottom of this page



ESU Lokpilot (v 3 & v4):

The lokpilot decoders have software settable performance characteristics (acceleration, max speed etc).  Address range up to 254 Motorola addresses, 2 auxiliary hardwired functions for smoke, telex etc.

Although these decoders have 28 speed steps available in Motorola mode, only 14 speed steps are available using a 6021 or an intellibox.   A Marklin Central Station (or ESU ECOS) allows the utilisation of the full 28 speed steps.

Earlier iterations of this decoder suffered from Alzheimer’s*, especially bad if using an early 6020 controller.  Not so much of a problem when using an Intellibox or Marklin Central Station.  Version 3 (V3) of the lokpilot, is considerably better than its predecessors in this regard, and V4 has connection points on it specifically for outboard capacitors and "keep alive" circuitry.


*Alzheimer’s: If the power to the decoder is momentarily interrupted (dirty track etc), the decoder may forget what it was doing and start it’s acceleration curve all over again from zero, or (worst case with early 6020 controllers etc which don't refresh the commands), may just sit and do nothing until it is re-addressed. 



ESU M4 (MFX): 

ESU used to make Marklin’s MFX decoders for them.  Marklin and ESU had a parting of the ways and although Märklin's decoders are now manufactured elsewhere, ESU continue to market these in opposition to M.

Being based on the lokpilot series, these decoders have soft-settable performance characteristics (acceleration, max speed etc).  Address range up to 254 Motorola addresses, 2 auxiliary hardwired functions for smoke, telex etc.   A good cheap way to get into MFX technology decoders

The MFX decoders are hardware-wise, similar to (or maybe the same as) the lokpilot.  The characteristics are a bit different though.

This decoder has only 14 speed steps available in Motorola mode, but 128 speed steps in MFX mode. One needs either a Central Station or Mobile Station to operate these decoders in MFX mode and get the 128 speed steps.

In my experience Alzheimer’s seems to be less of a problem than with the lokpilot, although I’m not sure why because they are basically the same decoder.



Märklin 60902: 

Marklin's predecessor to the MFX age.

An application specific chip with 27 speed steps available in Motorola Mode.  The 27 speed steps are available with all controllers from the 6021 on, but some knob twiddling is required to achieve this with 6021 or Intellibox.  

2 auxiliary hardwired functions for smoke, telex etc

Addressing limited to 80 Motorola addresses.  Addresses are hard set by means of dip switches, and accel/decel and max speed are settable by potentiometer.

These decoders virtually never suffer from Alzheimer's.

A very smooth decoder, but requires the 5 pole high performance motor. (not usually good running characteristics with motor option 1.)

These decoders are no longer procurable as new items, but I do have an occasional one available.  








Conversion in a 3329 BR191 with an older 60902 type decoder:   Decoder mounted at the idler end (left). Motor end at right.

































Märklin 60760:

Released as a special offer by Marklin from time to time the 60760 is a very basic digital decoder.  The decoder is not obtainable as a separate item, but comes with a 5 pole motor kit to replace drum commutator motors only.  The Motor parts are incorrect for replacing flat (disc) commutator motors and the decoder itself is not suitable for driving the flat commutator motors because the motor control parameters (feedback etc) are not adjustable.

If it is desired then to use that decoder in, say, a SFCM lok, then one would need to separately purchase the motor parts necessary to convert the SFCM to a standard 5 pole high performance motor.


This 60760 decoder has only 14 sped steps available (Motorola mode) and, as it comes from the factory, no functions (other than lights), but is quite suitable for any locomotive where those extra functions may well not get used anyway.  Actually, although not spelled out in any literature by Märklin, f3 can be wired out from the decoder and used to drive an auxiliary function. (See decoder harness wiring).         A good cheap way of getting suitable locos converted.   I have some of these in stock.


ESU Loksound M4 (MFX): 

Decoders with sound.  Performance characteristics and statistics of the decoder itself is (or should be) about the same as that for the standard MFX decoders, although higher current draw makes good power pick-up essential.

Only 14 speed steps in Motorola mode, 128 speed steps in MFX mode;  Up to 254 addresses in Motorola mode, automatic registration with Central station; 2 auxiliary hardwired functions for smoke, telex etc.; up to 16 functions in total depending on the various sound functions programmed into it.  Software settable performance characteristics (acceleration, max speed etc).   This decoder can be loaded with various “project files” to reproduce authentic sounds that match the prototype of the locomotive it is to be fitted to.  Only the first 8 functions are accessible in Motorola mode (using a 6021 or intellibox type controller).  A Central Station is required to obtain all functions.

ESU supplies these decoders with a small speaker.  Where space permits, a larger speaker will give much better sound reproduction.


The new Märklin Sound capable decoders (60945, 60965 etc).  I have now fitted several of these and found them to be quite good in operation.   Nothing wrong with the sound quality, but they do seem a little less versatile than their ESU cousins at this stage.  Marklin don't (yet) have as many pre-built sound files on their website for downloading as ESU do, and the loading of sound projects is a little more cumbersome.  One can however load ones own sounds into the decoder via the mDecoder tool and the sound programmer, so it's not all bad.  The other plus is that they're several dollars cheaper than their loksound rivals, so that's a bit of a bonus as well.  If Märklin happen to have the sound file that you want on their website, I think they're a pretty good bet.



What do I Recommend?   It depends on your budget and what you want to pay for.  


The Marklin 60760 decoder/motor is a good cheap way of going digital, but only for a locomotive that has no more than 1 extra function, and only if that particular loco is currently fitted with a drum commutator motor.


The ESU M4 (MFX) decoders are quite good and are current technology although the 14 speed steps are a bit limiting with a 6021 controller.   

The recently released Marklin 60942 and 60962 decoders look equally as good on initial testing, and don't suffer from the 14 speed step hang-up (27 or 28 speed steps in motorola and DCC mode respectively; 128 speed steps in MFX mode)  I have tested these with good result, (See a short report on my testing of these decoders), but they are yet to be thoroughly proven under normal operating conditions.)    



In cases where MFX technology is not desired or required, a standard ESU lokpilot decoder will normally give satisfactory results. This decoder may be a good choice if using an earlier controller, and has the advantage that it can also be run in DCC mode if desired. 

The latest Marklin Central Station controllers and also the ESU ECOS, have the ability to specify either DCC or Marklin protocols on a per decoder basis.



I haven’t included pricing in any of the above options because there are too many variables.  E.g. there is a vast difference between wiring a decoder to a roomy V200 diesel locomotive with no additional functions, and fitting the same decoder to a steam locomotive (tender or body?) with functions wired to smoke unit and telex coupling.   Also, decoder prices are apt to change a lot more rapidly than the frequency of my updating this web site, so any prices I published would soon be out of date.


Email Kevin with your loco type and he should be able to give you all the options and a reasonably accurate estimate of costs.


My pricing will allow for the servicing and mechanical inspection of the locomotive, but obviously, prior to inspection it can’t allow for remedial work such as re-setting wheels on steam locos, replacing defective gears etc.





Test Report on the new Märklin decoders (60942, 60962)

I elected to do a test install in a large-wheeled steamer rather than an elok or diesel because if one was going to have irregularities in performance, the large driving wheels would be more susceptible to it. Accordingly I used the version with the wiring harness (60962) and wired it into a venerable old 3005 that I'd just finished servicing.
First impressions of the decoder out of the box: The wires are very thin (even more so than on a lokpilot) and looked very delicate. My first step then was to do what I always do with the lokpilots - run a thin bead of hot melt glue along the line where the wires come out of the heat shrink, thus avoiding the necessity of having to resolder wires to the decoder. One plus is that the wires are considerably longer than those on the lokpilot, probably long enough to reach from loco to tender (depending on the model), thereby avoiding joins.


Differences: 60942 (21 pin) and 60962 (wiring harness) versions

Another interesting point is that the cable colours on the 60962 are according to NEM DCC standards, but on the 21 pin version with motherboard, the motherboard cables are standard Marklin colour scheme.

The cables on the supplied 21 pin wiring harness motherboard are also less fragile looking than the cables on the wiring harness version and in fact look to me the same as the wires on the venerable 60902 type decoders of a few years back.

The major plus with the 21 pin version though is that it has 4 aux functions (plus the 2 lighting functions) as standard out of the box, so if one happens to want directional headlights plus cab lights, plus a smoker, plus a pair of individually operated telex couplings for instance, then there's enough function outputs to do all that.

Programming: Initially, after wiring in, I left everything at default and tried a test using my ESU lokprogrammer "virtual drivers cab". (The lokprogrammer can't read or program these Märklin decoders, but I like doing initial power ups using the "virtual drivers cab" because with its 300ma power regulation it's incapable of blowing up a decoder even if one should make a total hash of the wiring connections).
At this point I discovered that the DCC address and the Motorola address are settable separately, and in fact the decoder defaults are DCC Address 3 and Motorola address 78. (That took a few minutes to figure out too, maybe I should've read the instructions)  The next step was to put the loco on my test track and let it auto register in MFX mode with my CS2.  No problems with that, and I spent a happy hour or 2 playing with various CVs for functions and motor settings.


CV52 is a nice addition where one can tell it what type of motor one has installed and it supposedly tweaks the motor feedback parameters to give optimal performance. Certainly in the short session I had I was unable to discernibly improve the motor control CVs from the default and I finished up contenting myself with winding the top speed down considerably and opening out the acceleration and braking delay to the large values I prefer.  I'm not saying it'd be impossible to improve on the defaults, but certainly
there's not really much wrong with them for the loco I was playing with. 

Re the mechanics of programming, one can tweak anything and everything with the CS2, and a useful subset with a CS1 (which I also tried). I don't find the Programming interface in the CS2 particularly intuitive but it does get the job done ok.  After the session with the CS2 I Also tried DCC mode CV Byte programming with my Intellibox: Even though the Intellibox returned "error" after writing each CV, it did indeed write them and one can read them back OK to confirm this.

Overall I give the decoder a "very good", a worthy contender for the lokpilot and with a few advantages (perhaps smoother control, but at least as good; MFX, DCC & Motorola all in one decoder; 27 speed steps in motorola mode (Vs 14 for the lopi-M4); amplified  aux function outputs (21 pin version only); and the ability to use it as a function decoder using the motor outputs as auxiliary functions (untried yet). 

The decoder responds to the various digital protocols in a hierarchical fashion.  It will always respond in MFX mode if there's an MFX signal on the track, and DCC and Motorola commands will be ignored. Similarly if no MFX but DCC is present on the track, then Motorola is ignored. Motorola will only be used if the other 2 protocols are not present. CV50 though, does allow one to turn off unused/unwanted data formats in the decoder and to check this out I tried disabling MFX mode on the decoder. That enabled it to be controlled in Motorola mode even though an MFX signal was present. It looks like that'd provide a good answer if ever you had one of those problems where the MFX registration process got itself tied in a knot.