I own the original set ( for approximatively 30 years ) and it has 3 gears, but you're right without motorization only 2 were able to spin the fake engine, the 3rd put too much stress.
first post on eurobrick !
it seems for me that the new set has already 3 gears like the original set, but shame that it lacks differential...
edit : after studying a bit more the pdf it seems there is only 2 gears (plus maybe a neutral position ?)