Loz Blocks

If they genuinely are 'normal' lego type bricks I agree they could be motorised very easily, probably the easiest way would be to do a 'Sun' and use a 9v motor bogie as you say either in a tender or a carriage/wagon depending upon which model you're motorising. That is assuming the wheels these ones are fitted with do actually rotate, I'm not convinced they do based on the pictures/videos I've seen. In which case you'd need to replace the wheels/chassis also to support axles etc... Again doable if you can use standard lego components, but still more work than is ideal, even if you were to use a 9v bogie you'd need to have a suitable hole in the chassis for the connecting pin.

Maybe I'll take a punt and try it, although the downside is I can't find them anywhere near as cheap as Ucwepn quoted, nearest I found is nearly $50 for a set of four and even then they come without the boxes etc...