A random thought that I've had for some time, knowing that the power of cars is measured in horsepower and after seeing how they use ponies to pull trains.
BTW, it's not just the ponies here that do all the work, the cars also help them gallop faster. (Don't ask how or why, it's a cartoon. Either that, or...magic.
Applejack and Rainbow Dash (c)
Ford Mustang GT
Dodge Charger R/T (the number 8 on it is the same racing number Applejack had in Fall Weather Friends)