How to motorise your HO scale Sydney O Class Tram

The O class tram has always proven a challenge to motorise in HO scale as the open seating compartments above the bogie section makes it difficult to install a standard motor bogie.

In designing this model I decided to use the BullAnt Gozunder bogies in connection with a half floor motor in the centre enclosed section of the tram. To connect the motor to the bogies I have used the Telescoping Cardan Shaft Kit all available from Hollywood Foundry.

In this blog post I will take you through the process of installing this equipment in the 3D printed model tram which you can order from Shapeways.

List of required components:

– 2 x BullAnt Gozunder bogies with a wheelbase of 16.5mm and 7.6mm wheels. More Info

– 1 x Gearbox for 16 Series Motor, 2:1 ratio with flywheel and a 1620 motor. More Info

– 1 x Telescopic Cardan Shaft kit 2″ More Info

HO Sydney Model Tram Mechanism

Here are the components laid out ready to install. In the top left are the two Gozunder bogies. The bottom left is the chassis model which can be 3D printed from Shapeways. In the bottom right is the shaft kit and in the centre the half floor motor.

The first step is to mount the motor on the chassis. As you can see in the image below the tram body is quite narrow and the motor mount overhangs the chassis.

HO Sydney Model Tram Mechanism


The mounts can be easily sawn off or cut with a Dremel and filed smooth. Mount the motor on the chassis with either some glue.

HO Sydney Model Tram Mechanism

Next the bogies can be secured to the chassis.

HO Sydney Model Tram Mechanism

The bogie at the gearbox end of the motor is very close to the drive shaft. The two black plastic couplers will need to be removed in order for the components to fit as can be seen in the next two photos:

HO Sydney Model Tram Mechanism

And with the couplers remove and the bogie the correct way round:


06I would have liked to link up the shaft on both bogies but this one is too close and would prevent the bogie from swivelling.


We will now install the shaft. Turn the model over and measure the shaft length.

HO Sydney Model Tram Mechanism



Cut the shaft to length and insert the spring and ends:


HO Sydney Model Tram Mechanism

The shaft is now ready to insert.

12Check the bogie swivel to ensure the shaft doesn’t spring out:


Solder up the wires and insert a decoder if you wish and the model is ready to run.

HO Sydney Model Tram MechanismTurn the model on it’s side and insert two securing screws to hold the chassis to the model.

HO Sydney Model Tram Mechanism

HO Sydney Model Tram Mechanism

You can blacken the flywheel if you wish to hide the motor a bit more.


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7 Responses to How to motorise your HO scale Sydney O Class Tram

  1. Rob Nesbitt says:

    Brilliant work. Thankyou for the photo tutorial; I am inspired to try it myself.

  2. Alex says:

    Hi Joseph,

    Can you tell me the name of the font which the numerals come from for the numbers on the ‘O’ Type Tram. I’ve seen the gold leaf numbers on the side of the tram but I can’t find them anywhere. If I knew the name of the font type that would help.



    • modeltrams says:

      Hi Alex,
      I’m not sure if the font actually has a name. I’ve always referred to it as the Randwick Workshops font. Not sure of it’s origins. I’ve attached a pic of the drawing number from Randwick Workshops but to save you time I have a whole lot of gold leaf decals for NSW trams.


      Randwick Workshops Font

  3. If the large flywheel on the Gozunder was not on the end of the motor (I beleive it can be left off by Hollywood Foundry if not required.) , then the motor unit with the gearbox attached could be moved to the centre of the chassis component. This would allow each Gozunder gearbox to be attached to the motor’s gearbox with a shorter sliding-shaft link.
    The need for the sliding-shaft link to the motor is due to the swivel point of the shaft being well outside the pivot point of the Gozunder bogies. If it was closer to the pivot point of the Gozunder bogies it could be a much better design.

    • modeltrams says:

      Hi Andrew,
      Yes this could be done but I really need the flywheel for my layout. I have many points and I enjoy running my trams a prototypical speeds. The flywheel drive on the Gozunder provides for really smooth running.

      The chassis is separate from the tram body so you could always scratch build a chassis yourself if you wish to run a Gozunder without the flywheel.

      Thanks for your comments.

  4. Chris Davison says:

    Would it not be possible to have the transfer gearbox between the motor and the flywheel so that the output shafts could be in the centre of the chassis giving equal length shaft to either end?

    • modeltrams says:

      This might be possible but is a question best directed to Hollywood Foundry.

      This wouldn’t work for me though as the shafts would end up being too short to allow for the bogie swivel I need for the ultra tight curves on my layout.

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