Reconditioning and remotoring of roco 04146A locomotive

I recently brought a Roco 04146A loco (DB BR103) for a good price. Problem was that it had some missing pieces and looked really dirty. So i bought it and set about doing 2 things.

1: Cleanup the loco and adding the missing details

2: Remotor the loco. Originally it had a really chunky motor that drew almost 2amps peak. I wanted to replace it with a more modern can motor, skew wound.Also replace the lights with LED’s.

So here’s the loco after i bought it: The loco was dirty, the pantographs were coming off, some roof detail was missing.

That is a huge power hungry motor inside !


Removed the old motor and the truck assemblies. I ordered a “Kato HM5” motor. This motor had about 1amp peak draw @12v. It has 2 long 2mm shafts. Below is where i milled the chassis to accommodate the HM5. Milling was easy as the material was diecast. It was easier on the endmill than when compared to aluminum.


Then turned 2 flywheels for the motor to mimic the prototypical loco momentum.


The truck wheel assemblies were removed. The gunk oil cleaned. Cleaned the wheel power contacts. Then i re-greased the assembles with a PTFE(Teflon) based synthetic grease. Much better than the traditional petroleum based greases.


Here’s the assembled chasis with HM5, the flywheel, LED lights and a Digitrax ‘DZ125’ z scale decoder. It was so tiny, it fit right on top of the motor. I had to make a seperate wiring board to accomodate the new wiring.

A tip here : You want real fine stranded wires here. 32Awg works great. If you can’t get any or if you think prices are too high, try ‘‘ website and search for 32 gauge servo wires. They are awesome!


Closwer view of the motor. The motor is secured to the body by means of zip ties. They held up quite well.


The assembled loco with the new mods. The top was giving some wiring detail by forming a nice 14awg bare copper wire and painting it with a hobby paint. Just like the prototype.



The real test of the loco. Worked great on my DCC layout!



I am a computer engineer living in the beautiful city of Austin,TX. While my day job is designing computer chips, I love to dabble in woodworking, metalworking, r/c and electronics.

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Posted in Model trains
3 comments on “Reconditioning and remotoring of roco 04146A locomotive
  1. Dennis says:

    How did you remove the body from the bottom section? I was just given one of these locos with no instructions, and I’d like to open it up to see if it would be possible to install a DCC adapter.

    • rkovvur says:

      Yup, i ran into the same problem. It was simple actually. Look at the last photo of the loco with the lights on. Near the pantographs, you will see 2 screws. These are the 2 screws securing the shell to the lower chassis. remove the 2 screws and the shell comes out

  2. Dennis says:

    I can’t believe I missed those. Thanks!

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