I disagree.
There were many many far better options.
Certainly not all the tank cars were at risk
If they were, you vent them and fly in some fiberglass swimming pools or anything but what they did.
If it is really that volitile it should not be traveling in a statistically unsafe manner.
If they were, you vent them
Which form of controlled release was best may be debatable, but the alternative to a controlled release was an uncontrolled release, which seemed likely to happen at some point as the cylinders were heated by the fires.