Physics
Inside a steam locomotive
Follow fire, boiler pressure, cylinder expansion and the coupling rods that turn the wheels.
Try this
Follow the numbered cutaway. Coal burns on the grate; hot gases heat water around the fire tubes. Steam passes through the regulator into the cylinders. Pistons drive the wheels, then exhaust steam enters the blast pipe beneath the chimney.
The model and its limits
Two double-acting cylinders, exact slider-crank geometry, approximate expansion and a lumped saturated boiler. No detailed valve-gear timing, combustion chemistry or multiphase boiler flow.
Equations used in the module
Equations x = r cosθ + √(l²-r² sin²θ) τ = (p-p_a) A |dx/dθ| F_t ≤ μ M_d g
