Heljan Nohab MY project

  • I had a lack of long time projects :S so I got myself another one.

    Bought a used Heljan 44801 Nohab MY with unknown history.

    It's an unpainted (brown plastic) model with high mileage (visible wear on the wheels) and some parts missing.

    But it's beautiful anyway :love:

    There are some problems that needs to be fixed so that it can be driveable.

    The three biggest problems is:

    * it is analog, DC.

    * I need to put Lenz couplings on it and there are no accessorie bag in the box

    * when I try to drive it with DC, lights are working but it is not moving

    Well, time to address the problems.

  • Good morning,

    well, might be an interesting job. And yes, the MY is a beauty! 8)

    When trying to drive it, what current is supplied by your transformer? With the original motors installed, the older Heljan locos need a high current to move in general. Maybe your transformer hasn't enough power?



    Betriebsleitung der Werkelburger-Industriebahn


    Die Kritik an anderen hat noch keinem die eigene Leistung erspart. (Noël Coward)

  • The only power is diesel power!

    Maybe there’s an issue with the dcc socket. Try to put power directly to each motor. By this you can test the amp draw separately. It should equal with booth of them. So you con check by the way, if it should arise problems with dcc in your ongoing project.

    Modellbahn ist Spaß - und den definiert jeder selbst!

  • With the top of it is easy to see that the motors are running but the wheels are not :(

    So it is a gear problem. I don't know if it is a common problem with this loco,

    but Heljan has apperantly problem with broken plastic gears on other locos.

    Pics are coming later (today, I hope).

    There is no dcc socket. It is just an analog PCB. That's why it is a problem.

  • Yes, it is a common problem with those Heljan gearboxes. Unfortunately Heljan isn't able to deliver sparparts as far as I know. There was a member of the Gauge 0 Guild some years ago, who offered spare gearwheels for british Heljan locos. Maybe it would be an option to contact the Gauge 0 Guild.

    I'll keep my finger's crossed :thumbup:


    Betriebsleitung der Werkelburger-Industriebahn


    Die Kritik an anderen hat noch keinem die eigene Leistung erspart. (Noël Coward)

  • I have already solved some of the problems. Was going to write it in the second post but I get interrupted all the time. Women! :cursing:

    Beginning with a view of the project:


    Then we can begin with the gear problem.

    There are two identical boggies with one motor each, looks like this:


    And if we take it apart it looks like this:


    The two plastic gears next to the motor shaft is cracked, same on both boggies.


    There are two separate plastic gears pressed on the same axle, the small one is cracked and doesn't rotate:


    To be continued tomorrow..... :)

  • Tomorrow is today :)

    Visiting Heljan's homepage made it clear that there are no spare parts for Nohab MY, except for handrails.

    But there seems to be some plastic gears for some other, strange locomotives in scale 0.

    They look the same, but a picture of a spare part in a plastic bag doesn't tell much.

    Well, I sent an email to Heljan's service department with measurement and number of teeth on the gears that I need,

    and asked if that was any of their spare parts that would fit. Got a quite fast reply stating:

    "This item has been sold out for more than 10 years and we no longer carry spares for this item"

    I took a chance and ordered two look-a-like gear sets and hoped for the best.

    Price for the part, around €9 each pair isn't so bad, but they have a fixed shipping cost at around €30,

    even for the smallest part. I don't give Heljan's service any stars.

    Well, does the Gear assembly for O Class 35, 47 V1 & 37 V1 (2010)+Class 55 fit Nohab MY?


    Nope, but close enough. New one to the left, old to the right:


    The only difference is the length of the axle, the new one is 1mm longer on the top.

    A simple solution would be to file it down but I'm afraid to damage the plastic gear.

    So I went for a more simple solution, made the axle hole in the boggie 1mm deeper:


    After checking that everything is rotating freely it's time to assemble it again:


    Hade a short testdrive with the boggie on the testtrack. Does it work? YESSSS!!! :thumbup:

    Made the same operation with the other boggie and then I call this problem solved :)

    Next problem.......

  • Regarding the cracked gear, could it be, that Heljan manufacture their engine in the same China company like Bachmann.

    They have the same problem with their On30 range of engines, where some original sealed locomotives had cracked gears when you open the package.

  • Hello

    Weaver and Atlas/Roco had the same problems with broken gears and they did not get it from China in the past as far aus I know.

    Ist seems the Chinese had the wrong tutors😁

    I got spare gears for a Bachmann from http://www.kkpmo.com, I told them what I need and they made it. All in all I paid 14€ in 2019 for 2 gears, 1 narrow fit and 1free running.

    Maybe it helps someone.

    Viel Spaß beim Basteln


    Gruß Olli


  • Regarding the cracked gear, could it be, that Heljan manufacture their engine in the same China company like Bachmann.

    They have the same problem with their On30 range of engines, where some original sealed locomotives had cracked gears when you open the package.

    I have the small Bachmann On30 diesel engine, and it does have a cracked gear. :(

    It's on my neverending todo-list :rolleyes:

  • Over to the next problem, couplings.

    I want to have Lenz couplings because they work very well and all other rolling material has the same.

    The ideal thing would be some kind "telex" couplings as on Lenz locomotives, but as I don't have any of these

    and don't know if there are any to buy somewhere, I decided to 3D-print a holder to the standard Lenz cuopling.

    It will do for now, the important thing is that I can use it.

    The holder was drawn in Fusion 360 and it looks like this. Thera are two printed parts, the red one is mounted on the chassie

    and the green one is holding the coupling and can rotate a little.


    I cut a small spring in two halfs and mounted them on each side so that the holder self-centers.


    And with both mounted


    The height is correct, maybe I need to adjust the length, but that's easy.


    If anyone knows if Lenz automatic couplings is available somewhere, please let me know :)

  • Hello rcmodeler,

    if you can wait a bit, I'm removing the Lenz automatic coupler from my 212 soon. I only use screw link couplers and don't need them any more. Just contact me by pm.



    British Railways (Western Region) Ende der 50er Jahre und jetzt irgendwie doch mal wieder 0e ;)

  • NEW problem.

    I don't know what the metal parts are made of but it is quite brittle (someone in another forum called it monkey-metal).

    Anyway, when I took the boggie apart for changing the gears I noticed a crack in the motor bracket, and on a test run

    with a boggie with some load on, the motor bracket snapped of and the motor got loose.

    There is a similar crack on the other boggie at the same place.


    My first idea was to simply make a new motor bracket and drill some holes in the monkey metal for some screws,

    and when I did that another part snapped off :(


    Time to make something drastic X(

    I've been playing around with Fusion 360 for a while and I thought I will try to make a 3D-print of a boggie.

    Just using a caliper and a lot of patience this came out of the printer:


    Well, this was not the first attempt but it is the final prototype.

    It is PLA and it is easier to see any mistakes when it's not black.

    Trying to put everything together:


    Not too bad:


    Power pick-up:


    they are just pressed in place just like these:


    and it looks alright:


    does it work?


    well, so far, so good. Sounds ok.

    Probably going to use some other type of plastic, and another color, of course.

    But anyway, not bad at all :)

  • Been a long time since last update but there has been some progress.

    The locomotive is going to run on dcc-track so the original analog pcb-board is no good.

    I made a diy test on a lab-deck with a rectifier, step-down converter, Wemos D1 mini and a motor driver:


    It takes power from the track and I can control it from my wireless handcontrol with wifi and mqtt.

    It works as it should and I can program the functions I need.

    But there is no sound :(

    I could probably make something with a soundmodule but it would not sound like the real thing.

    So I had to buy a sounddecoder. I don´t know much about the decoder market but I have heard about Esu.

    Esu loksound 5L was ordered with soundfile "TMY TAGAB NoHAB" installed.

    I hope it is able to drive the two motors. It looks like this:


    I made a new adapter card that would fit with the same mounting holes as the old analog card:

    IMG_20221118_133525_50.jpg?dl=0  IMG_20221116_154041.jpg?dl=0

    If I mount it with the decoder on top, then there is 2-3mm before it touches the fan motors.


    If I mount it upside down there is plenty of space, so I go for that:


    and here it is with resistors for headlights and the connectors that I use now.


    The blue thing that is glued on is a step-down converter for the fan motors.

    It can be mounted anywhere. The fan motors starts at just 0.8 volt and the

    step-down converter can go down to 1.0 volt, so I set it to 1.0 volt.

    Then the fan motor noise is very low.

    Moving on.....

  • Loksound require loudspeaker. I think it's originally located in the tank assembly.


    Holder for tank and small speakerIMG_20221118_231609_50.jpg?dl=0

    but a large locomotive needs a large speaker :P


    after testing different places to mount the speaker I ended up with this solution


    I made a new tank assembly with Fusion 360 and a 3D printer that holds the larger speaker

    IMG_20221122_072959_50.jpg?dl=0 the speaker fits like a glove


    and mounted on the chassie


    it will need som some sanding and finishing but I see that problem as solved.

    Maybe it will be running around christmas :)

    Moving on....

  • Made some changes to the motorboggie. On the old version I had to mount the motor holder

    after the boggie was mounted on the chassie. That was not so easy.

    Old version:


    new version:


    Also changed the power pickup. The old one used the power pickup as end stop against the metal chassie.

    This could probably never happen, but anyway....


    took a bit of 0,8 mm wire from my mig welder (can be used to a lot of things) and bent it to the right form,

    and printed a small holder:


    So now I have two complete motorboggies ready to mount :)


    Moving on....

  • The last things that needed to be done was cutting out some material from the "plough" (or what it is called),

    so that the Lenz coupling could fit:


    then paint the chassie black, mount it all and hope for the best :S


    All parts have been test mounted before but this is the first time everything is put together.

    And here it is on its wheels on my short testtrack:


    It seems to be working but we will see how it performs when I take it to my brothers small layout next week.

    Going to make a short video of it :)

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