History Specials (TV Series) 101 Inventions That Changed the World (2012) User Reviews

Number 52 had a wrong comment

[sboynton-16578 · 9/10 · 27 July 2022]

Number 52 was "differential gear" for a car but they also said that if they didn't have a differential that a locomotive would go off the tracks. Trains do not have differentials they use the sort-of cone shaped wheels so that way when it leans around a corner, it goes to a smaller part on the wheel.