Video explanation
The reconstruction follows opposing steam locomotives through approach, collision, boiler explosion and wreckage, comparing the sequence with historical photographs. Displayed speeds, energies and timings belong to the reconstruction model, rather than being direct measurements from the photographs.
Energy grows with speed squared
Kinetic energy is mv²/2; a collision dissipates it through deformation, fragmentation, heat and sound.
Impact and explosion differ
Impact dissipates motion energy; boiler rupture also releases energy from a hot, pressurized system. Speed alone does not explain flying debris.
Photographs constrain reconstruction
Photographs constrain positions and wreckage shapes but do not uniquely determine acceleration or every fragment trajectory. The animation is an explanatory reconstruction.