An awful lot of variables so strictly “order of magnitude” (the physicists get out of jail free card!) number…
The column diameter of the train is ~ 30 to 50m. Remarkable to consider that the meteoroid itself might only have been a couple of mm in diameter. The atoms evaporate off at a few km/sec but bump into the atmospheric atoms after a few free path lengths, a few metres then diffuse into the atmosphere over however long depending on size, mass, density, composition, velocity etc etc.
Most of those we have little or no idea about…!