The mysteries of Horsepower and other things explained

To simplify: Torque determines how steep a hill you can climb. Horsepower determines how fast you can do it.
TNM&O buses used to be geared for running flatlands. Greyhound busses were geared for more general purpose running all over the country. All being equal for both otherwise, Greyhound busses could make it up mountains in the Rockies whereas TNM&O charters could not.