Steam Power

In a park near our home there is a steam engine on display. It was built in the 1940s, and so was one of the last of its kind. It's enormous

the wheels being as tall as I am. There is a sign nearby that says that the engine weighs 675000 pounds, and had 55000 pounds of pull. It's very impressive. Most amazing of all to me is the size of the piston that is positioned between the lead wheels. It seems so tiny! You can just make it out in the picture above (click to zoom). Here is a schematic of a steam engine in more detail:

which I obtained here. Amazingly, the entire 55000 pounds of thrust are generated by that piston (or half of that? Do the pistons on each side work together or in sequence?). The sign near the engine said that the steam pressure was 250 pounds per square inch, so a piston with a diameter of 17 inches might theoretically be big enough. Maybe you had to be there, but seeing the enormousness of the engine in comparison to size of the piston left me dumbfounded. The piston didn't even look like it was attached well enough to take that kind of force.

In any case, the power of steam is amazing.