I have got a bit of a soft spot for Japanese brass. For years I had looked in envy at the adverts in old magazines. And every time I see one in the flesh I am usually amazed at the quality of them.

The detail on models 30 years old is often superior to what we get on modern ready-to-run models.


But the difference is that I can sometimes now afford to buy them if the price is right.

I saw a Balboa GS4 being advertised and put in an offer and to my amazement I won!


The Balboa GS4 is admittedly not a rare model. they were churned out in their thousands by the likes of Katsumi or Samhongsa.

Balboa imported their GS4's from both manufacturers but my particular model is a Katsumi model.

Mechanically it was in pretty good order. The wheels were fine with near perfect plating. The gearbox was perfect but the motor was drawing 1.5 amps!! I didn’t particularly wish to set fire to my layout and so I decided a new motor was in order.

I actually don’t mind this. There are some people who would be horrified at whipping out an original motor, but the improvement in running qualities from such a simple project almost always makes it worth doing.


To start with, the old motor had to come out. This really was a monster.




Instillation of the new Mashima motor turned out to be simple enough.

There was loads of space.

I have taken to sticking the motors down with a silicone adheasive. its really ideal for this application PROVIDING THE SURFACES ARE CLEAN.

It gives a nice cushion for the motor to sit on and gives a beautifully smooth quiet ride.


I chose to use a NWSL cardan shaft to drive the gearbox. fairy simple to install and again, it isolates the gearbox from the motor giving a much smoother ride.

The slight misalignment is nothing like enough to cause a problem.

The only other thing to concider is that in the origonal instillation, the gearbox was held vertical by the plastic universal joint. So a brass torque bar was made to take care of that.

After a quick test run, I was amazed at how nicely this loco crawls along. Almost silent. All wheels are sprung on this model and with an almost silent transmission it just glides along the rails.

Happy Modelling