The #thing that is catching fire is the Condensate that is part of the crude mixture. Condensate is used to make gasoline and to mix different grades of diesel and jet fuel. It has a high propensity for generating static electricity on its own! All it needs is a proper air mixture to ignite it usually found at the vent.
Because of this your #gasoline in your car has a chromium additive "FISK" or similar. The idea here is to allow the static electricity to drain off the surface of the gasoline in the tank to walls of the car keeping it safe to drive while sloshing around.
The crude oil has no such additives and when the crude is jostled and splashed around in the tank cars the liquid retains it's static charge. If this charge is discharged at an air source with a proper minimum air mixture it will ignite; explode.
Supposedly new tank car design has nothing to do with curing this problem. There is no chromium additive to the crude that is in them because this additive would affect all product made from the crude which is not desirable for a number of reasons.
#So long as crude is shipped in tank cars there are going to be explosions and fire.
A bit on static and petroleum.
There was a time when #oil tankers were blowing up while travelling light on the ocean. It was suspected for years it was mines left over from the second world war.
Ireland would get its oil from Venezuela and it was loaded boiling hot. By the time the tanker got to Ireland and other points north, the crude had cooled more or less solidified. The ships prepared for this had giant sprinkler systems built into these mammoth size tanks. Going south the oil residue would warm in the tankers. In doing so it would give off its condensate into the tank atmosphere.
When the ship turned on its sprinklers, the sprinklers (free falling spray of sea water) would create sufficient static electricity for ignition.
More times than not the resulting residue could be pumped into the ocean leaving the tanks clean and empty. However; occasionally the conditions existed for a lightning storm in the tanks blowing the tankers out of the water.
The same risks remain prevalent in rail transport of bulk flammable liquids. Safety generally depends on keeping a vapour rich atmosphere in the tanks offering no ignition source. But, the static is always there and if it is in a collision or upset chances are in favor of an explosion.
Petroleum products in trucks.
Tanker trucks were catching fire in the oil patch. The drivers were standing by the tanker trucks watching for a tethered perfex bottle to appear at the vent. The fires seemed random with no explanation available. I was asked in as "The Dangerous Goods Training Center" and found their whole lack of knowledge of static electricity was putting them in harms way on a daily; hourly basis.
The crude that came out of the pipes was hot and carried a very high static charge from friction. Because it was hot a vapour rich area was formed in the void of the tank. As the tank filled, HVB and LVB (condensate components) was forced out of the vent on top of the tank leaving a vapor rich area around the vent. When the perfex bottle appeared at the vent it would discharge as polypropylene has a high propensity for collecting static electricity.
If however there was a light breeze blowing across the vent it would leave a lean air mixture at the vent perfect for ignition on static discharge.
Other areas was the filling of the trucks at the racks. They had long nozzles hanging on the racks unused opting instead for the lighter shorter foot long nozzle. Splash filling a flammable liquid was the norm. They learned a bit about static electricity and opted for the long spouts to fill the tanks from the bottom.
After 2 such seminars the oil companies barred me from going back. I advocated clean coveralls and coverall change being available. I advocated proper earthing procedure and some racks were not equipped for proper earthing. My seminars would last up to 6 hours as I handled all questions. This apparently too much for oil to take.
Point is it is another venue where tankers blow up and that is not going to change. Oil companies should check their Liability Insurance if they wish to continue.