Re: lbf. vs Tractive Effort

Poundforce, lbf, #, pounds, etc. - all the same - are a force.

Horsepower - is a unit of power. Power is energy per second; energy (many different ways to arrive here, but for our case) is force times a distance. Force at the piston, times crank radius gives you your energy. The faster you can do that, the more power you get.

If that doesn't make sense - think of it this way: More energy per second, more horsepower. This is why car engines can put out lots of horsepower - lots of RPM's. In the case of a steam locomotive, the engine is directly coupled to the speed without shifting - hard to get that force per second going on. Hence why horsepower is not a great comparison for steam locomotives vs. other machinery.

Mark Huber
Hyce on YouTube