Here the repositioned motor and the drive train. A quick test showed that the 1:3 reduction gives an adequate travelling speed of the cars, whilst the motor still has enough power. Here I will point out that, IMHO, it is a great luck that Märklin/Metallus always kept the 1/2" spacement. Many Märklin-exclusive parts are a great enhancement for Meccano, for instance (as in this case) their special brackets and trunions for odd gear pairings.