I made quite a few changes including making it 1" shorter overall. The original (first published in MM Sept 1929) used the final un-numbered version of the clockwork motor, more or less what became the No. 1a. The gear ratio was very optimistic for the weight of the model but the options for changing it were limited due to space. I used a No. 1 motor which limited it to running forwards (the postwar reversing version would be ideal really) but made room for an extra 2:1 reduction gear. It chugged along nicely on straight Hornby 0 Gauge rails but the friction on the 2 foot radius curves was too much for it!