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…!
Cheers,
Bill.