Back in the early 60's, in high summer heat, at Paradise, I watched the Northern Pacific's EB Mainstreeter come flying into the depot and behind it, a grass fire started burning out away from the tracks in a "V" pattern, like the wake from a speedboat. Cause turned out to be the engineer applying sand to prevent wheel lockup while doing a heavy brake application, the sand got white-hot, sprayed out from the train, and voila! Instant ignition. All sorts of causes for trackside fires...