Although internal combustion engines may be high in horsepower, they're low in torque when held against comparable-sized steam engines. The reason is two-fold; related with both the thermodynamic properties of steam, and the simple fact that every stroke of a reciprocating steam engine is a power stroke, compared to a four-cycle internal combustion engine's single power stroke.
The end result can thus provide some interesting examples of this principle at work! In this instance, a 5" gauge 2-10-0, at a steam fair in Germany, hauling a full-size, standard gauge seven ton flatcar: https://www.youtube.com/watch?v=d5sxwJDVIrM
