Just one other disadvantage of the Portram bogies is that the motors run on a maximum
of 4.5 volts.
Removing the circuit boards removes the electronic gubbins that drops the 12 volts on the track to the 4.5 needed for the motor.
So you either need a special low voltage controller, or leave the circuit board connected to the bogie or be very, very careful to not turn the control knob above half speed. (possible but NOT recommended....especially at exhibitions
Also any pulse power controller is likely to fry the little motor as these put a full 12volt pulse to the track at all times.
Just another problem and expense
Have a good day