We were not fighters like them; we were cunning and cowardly, and it was because of our cunning and cowardice, and our inordinate capacity for fear, that we survived in that frightfully hostile environment of the Younger World.
Union Pacific's 4-6-6-4 Challenger steam locomotive #3985 is the largest operating locomotive in the world. Built in July 1943 and still used by UP for occasional excursion throughout the western United States, the 3985 weighs 1,073,900 pounds (537 tons).
Using the same formula above, setting the speed of the Planet type engine to 20 mph, at 30HP we get a maximum train weight of 70.3 Tons. Therefore, for the circa 1830 Planet type railway steam engine, at 20 mph, the horsepower to weight ratio was: 30 HP/70.3 Ton = 0.4267 HP/Ton.