Not a very valid comparison since modern TCs all have the motor in front of the spur gear. The SST layout was not an innovation so to speak since pretty much every yokomo TC had it before, amongst many, many others.
The earliest car to have the layout we have today was the original 415-or maybe Atlas or T.O.P. had it shortly before, i'm not sure. But if someone has a definitive answer to that, I'd be curious to know.
Funnily, I got a picture of an early XXXS prototype ( with CF top and bottom plate) and the motor was behind the spur.